Abstracts of Poster Presentations Tuesday, 17th of September 2019
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Trans R Soc Trop Med Hyg 2019; 113: S99–S140
doi:10.1093/trstmh/trz090 Advance Access publication 16 September 2019
Abstracts of Poster Presentations
Tuesday, 17th of September 2019
ABSTRACT
P002 between fevers ranges from 4 to 14 days. This surveillance data anal-
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ysis study will help to identify the trends of Relapsing fever in Addis
EPIDEMIOLOGY OF MALARIA IN KEMBATA-TEMBARO ZONE, Ketema Sub City with in the past five years and compare it with the
SOUTHERN ETHIOPIA: A FIVE YEAR DATA ANALYSIS FROM current status of disease which may give information on the trends of
2011-2015 Relapsing fever.
Aim: To analyse the surveillance data of Relapsing Fever in Addis Ketema
Addissie A., Lire A. sub city from 2012-2016 by describing its magnitude and distribution
School of Public Health, Addis Ababa University, Addis Ababa, among woredas.
Ethiopia Methodology: We conducted retrospective surveillance data analysis in
Background: Between 2000 and 2015, the number of malaria cases Addis Ketema sub-city by using secondary data that was recorded in
declined by 42% while the malaria death rate declined by 66% in the sub-city from 2012-2016 and analysis was done within one month (Jan
African Region. However, Malaria is a major public health challenge in 16/2017- Feb 15/2017).
Ethiopia, contributing 4% of all cases in Africa. It makes approximately Results: There were around 381 Relapsing Fever cases reported in the
68% of the population the country at risk. Therefore, this surveillance data past five years (2012-2016) among which about 69% was reported in
analysis was needed to analyze magnitude, trends, and geographical 2016 and among the total cases reported in 2016, again 52% of them
distribution of the disease in Kembata-Tembaro Zone from 2011 to 2015. was from woreda 07. In addition to that, in 2017 during five weeks of
Aim: To assess the pattern of malaria, incidence and prevalence in the reporting period there were around 30 cases reported from three Woredas
study area for the purpose of informing public health action. (Woreda 7, Woreda 1, Woreda 4). Depending on the number of cases they
Methods: A descriptive study was employed for analysis of data reported within the past five years Woredas are arranged according to
on malaria indicators from the Integrated Disease Surveillance and high risk area in descending order as Woreda 7, woreda 8, woreda 1,
Response System database for the years 2011-2015. The surveillance Woreda 9, Woreda 4, woreda 2, woreda 5, Woreda 6, and Woreda 3/10.
data were analyzed to show incidence, trends and variation in risk by The overall Cumulative Incidence rate of relapsing fever in Addis Ketema
reporting woredas (districts) by using charts, graphs and tables. sub city in the past five years (2012-2016) were ranges from 6/100,000
Result: In the Zone, the average estimated annual incidence of reported to 85/100,000.
total malaria in the overall population was 69 per 1000 persons and Conclusion: Within the last five years the trend of RF was increasing and
confirmed malaria were 54 per 1,000 per year over the five years (2011 to there were Outbreaks in Addis Ketema Sub-city starting from March 2016
2015). As of the calendar years 2011-2015, the annual incidence of total till now. Therefore, it is recommended to follow the trend of RF in sub-
malaria report dropped from 119/1000 to 9/1000 and reported malaria city closely and give appropriate interventions giving special attention for
in-patient admissions and deaths dropped from 1.7/1000 to 0.9 per Woredas those identified as high risk areas.
1,000 per year and 1.3/100,000 to 0.4/100,000 respectively. In addition,
laboratory test increases from 60% in 2011 to 90.2% in 2015.
Conclusion: We conclude that the magnitude of Malaria in Kembata Tem- P004
baro Zone declined (dropped significantly from 119/1000 to 9/1000) from ASSESSMENT OF KNOWLEDGE AND BEHAVIOUR OF CARDIO-
2011-2015. From all woredas, kedida woreda is most frequently affected VASCULAR RISK FACTORS AMONG ADULTS IN COMMUNITIES
woreda in the Zone. Even though different malaria control strategies were OF NORTH TAJIKISTAN
designed to roll back to its minimum level in Kembata Tembaro Zone,
still malaria cases were not decreased as expected. Therefore, the zonal Afandiyeva G.1 , Karimova G.1 , Mengliboyeva Z.1 , Arigoni M.1 ,
health department should maintain such reduction in both morbidity and Matthys B.2,3 , Prytherch H.2,3
mortality due to malaria. 1
Representative Office of the Swiss Tropical and Public Health
Institute in Republic of Tajikistan, Dushanbe, Tajikistan;
2
Swiss Centre for International Health, Swiss Tropical and Public
P003
Health Institute;
3
RELAPSING FEVER CASES SURVEILLANCE DATA ANALYSIS University of Basel, Basel, Switzerland
FROM 2012-2016 IN ADDIS KETEMA SUB-CITY, ADDIS ABABA, Introduction: Health literacy (HL) is a person‘s ability to find, read, under-
ETHIOPIA stand and act on health information effectively to make decisions about
Nesga D., Addissie A. the own health1 . Low HL has been linked to a poorer health status.
School of Public Health, Addis Ababa University, Addis Ababa, Aim: We have assessed the knowledge, beliefs and behaviour relating to
cardiovascular diseases, risk factors and related diseases (diabetes and
Ethiopia
obesity) among the adult population in a district in North Tajikistan in
Background: Relapsing fever is a recurrent febrile infection caused by 2018.
various Borrelia spirochetes transmitted either by lice (epidemic relapsing Methods: A mixed-method longitudinal cross-sectional study was used
fever) or by ticks (endemic relapsing fever). In both forms, the interval to measure the key indicators. The questionnaire had been elaborated
© The Author(s) 2019. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.
S99Poster Presentations
and validated by a national team of experts. The sample size was calcu- Methods: Wild rodents were trapped in scrubland across one site on the
lated following the WHO STEPS surveillance manual2 . slopes of the Asir Mountains in 2016 (Al Ous’) and four sites in 2017
Results: Overall, 217 adults were interviewed in 11 communities for the (Al Ous’, Al Jarf, Alogl and Wosanib). Following DNA extraction, the v4
baseline. Every fifth respondent (19%) had a good and half of them region of bacterial 16S rRNA was amplified by PCR, and amplicons were
(50%) a fair overall knowledge on cardiovascular diseases and related sequenced on an Illumina MiSeq.
risk factors. ‘Stress’ was most often mentioned (59%), followed by ‘high Results: A total of 7,802 ectoparasites were obtained from 74 rodent
blood pressure’ (45%), ‘poor diet’ (38%), ‘obesity’ (24%), and ‘diabetes’ specimens, including chigger mites, fleas (Parapulex chephrenis),
(20%). Gender differences were observed for ‘smoking or tobacco use’, ticks (Haemaphysalis erinacei and Rhipicephalus spp.), lice (Polyplax
whereby men 2.5 times more often cited this risk factor compared to brachyrrhyncha and Polyplax oxyrrhyncha), and gamasid mites(Laelaps
women (28% vs. 11%, respectively). Men of the older generation much lamborni, Ornithonyssus bacoti). Based on the morphology of the
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more often mentioned the risk factors diabetes – (28%) compared to scutum, chiggers were assigned to subgenera into 17 species, includ-
older women (9%), and high blood pressure (53% vs. 26%, respectively). ing four putative new species:Neotrombicula sp.n.,Microtrombicula
A majority of the interviewees (83%) believed that their own health aff.machadoi,Schoutedenichia.aff.thracica and Schoutedenichia sp. n.
status is self-paced, but almost half of the respondents (45%) have (Nadchatram, et al. 1974; Stekolnikov., 2013). Ectoparasite-associated
never tried to change their lifestyle. Significant gender-related differences bacteria were investigated using a 16S rRNA amplicon sequencing
were observed for eating less fat (men: 9%, women: 20%), eating more approach. Potentially pathogenic bacteria included Borrelia spp. in
fruits and vegetables (men: 40%, women: 1%), and controlling the own chiggers, Bartonella spp. in fleas, and Coxiella spp., Francisella spp. and
glucose level (men: 4%, women: 14%). Many respondents estimated Anaplasma bovis in ticks. Symbiotic bacteria with putative mutualistic
having opportunities, time and financial resources to change their own were present in fleas (Wolbachia and Spiroplasma spp.) and lice
lifestyle. Significant generational differences were found for having finan- (Candidatus Legionella).
cial resources with 80% of the younger interviewees declaring having Conclusion: This is the first survey of rodent ectoparasite diversity and
enough money to change their lifestyle compared 66% of their older zoonotic bacterial pathogens performed in the ‘Asir Region of Saudi
counterparts. Arabia. The chigger diversity in the region is especially high, and the
Conclusion: Applying the concept of health literacy in this way supports presence of Borrelia spp. in these mites should be investigated further
more comprehensive options for health improvement, disease prevention to determine if they might be vectors of Lyme borreliosis or relapsing
and a more successful disease self-management among individuals with fever.
chronic diseases.
References:
References: 1. Nadchatram, M. & Dohany, A.L., (1974). A pictorial key to the subfam-
1. World Health Organization. Track 2: Health literacy and health behavior. ilies, genera and subgenera of Southeast Asian chiggers (Acari, Prostig-
7th Global Conference on Health Promotion [cited 02.12.2014]; Available mata, Trombiculidae), Kuala Lumpur: Institute for Medical Research.
from: http://www.who.int/healthpromotion/conferences/7gchp/track2/ 2. Stekolnikov, A.A., (2013). Leptotrombidium (Acari: Trombiculidae) of the
en/ World. Zootaxa, 3728(1). zootaxa.3728.1.1.
2. The WHO STEPwise approach to Surveillance of noncommunicable 3. Mathison, B. A., & Pritt, S. (2014). Laboratory Identification of Arthropod
diseases ( STEPS) Noncommunicable Diseases and Mental HealthWorld Ectoparasites, 27(1), 48–67. http://doi.org/10.1128/CMR.00008-13
Health Organization, 2003. Switzerland : ncd_surveillance@who.int
P009
P008
VARIATIONS IN PRE-VACCINATION PLATELET COUNTS: DATA
THE VECTOR BIOLOGY OF ECTOPARASITES ON RODENT FROM FROM THE EBOVAC-SALONE STUDY IN RURAL NORTHERN
THE ASIR REGION OF SAUDI ARABIA SIERRA LEONE
Alghamdi S.Q.1,2 , Alagaili A.N.3 , Stekolnikov A.A.4 , McGarry Baiden F.1,2 , Ishola D.1,2 , Kowuor D.1,2 , Afolabi M.1,2 , Owusu-Kyei
J.W.5 , Darby A.C.6 , Makepeace B.L.1 K.1,2 , Lowe B.2 , Kohn B.1,2 , Otieno T.1,2 , Manno D.2 , Samai M.1,3 ,
1
Institute of Infection & Global Health, University of Liverpool, Leigh B.1,3 , Greenwood B.2 , Watson-Jones D.2,4
Liverpool, UK; 1
EBOVAC-Salone Project. Kambia, Kambia District, Sierra Leone;
2
Dept. of Biology, College of Sciences, AL-Baha University; 2
London School of Hygiene and Tropical Medicine, London UK;
3
Dept. of Zoology, King Saud University, Riyadh, Saudi Arabia; 3
College of Medicine and Allied Health Sciences, Freetown, Sierra
4
Zoological Institute RAS, St Petersburg, Russia; Leone;
5
Institute of Veterinary Science, University of Liverpool; 4
Mwanza Intervention Trials Unit, Mwanza, Tanzania
6
Institute of Integrative Biology, University of Liverpool, Liverpool,
UK Introduction: Platelet counts are important during vaccine trials because
of potential vaccine-associated thrombocytopenia (VAT). The EBOVAC-
Background: Rodents have become increasingly recognised as hosts Salone trial in northern Sierra Leone is a phase 2/3 safety and immuno-
of ectoparasites and reservoirs of numerous human diseases including genicity trial of the Ad26.ZEBOV, MVA-BN-Filo 2 dose Ebola vaccine regi-
scrub typhus, bartonellosis, Lyme disease, and plague. Vector-borne bac- men developed by Janssen. In this trial, platelet counts were assessed at
terial zoonoses associated with rodents are a particularly large group least twice during pre-vaccination using the same laboratory procedures
of diseases that are emerging/re-emerging worldwide (Mathison & Pritt, and equipment.
2014). Aim: To describe variations in platelet counts and identify determining
Objectives: This study aimed to define the taxonomic diversity and factors.
bacterial microbiome of ectoparasites collected from wild rodents in the Methods: We compared platelets counts at two pre-vaccination time
‘Asir Region of southwestern Saudi Arabia, with a main focus on chigger points, at least 1 day apart and categorised the variations into those that
mites (family Trombiculidae), the vectors of scrub typhus. varied within 25%, and those that varied by > 25%. We used logistic
S100Transactions of the Royal Society of Tropical Medicine and Hygiene
regression to explore how variations were related to gender, age, area mainly in adults (56% of cases), all cases of malnutrition were among
of residence and days between tests. children aged 25% were associated of locally-determined normal laboratory ranges and use of short pre-
with being female (OR=1.37, 95% confidence interval, C.I. 1.06-1.84, screening questionnaires may help to conserve resources in future trials.
P=0.03). Children aged 1-3yrs were more likely to have variations of Malnutrition among children in this population needs to be addressed.
>25% than adults (OR=5.04, 95% CI 3.45-7.35, P28
days and 14-28 days between tests were associated with variations of
>25% (OR=1.6, 95% CI 0.64-4.41, P=0.287 and OR=2.05, 95%CI 1.51- P011
2.79, P25% variation were age (1-3yrs) and number ADDRESSING HOTSPOT TRANSMISSION SANTIAGO DE CUBA,
of days (>28days) between tests, (P14 Epidemiology Dept., Tropical Medicine Institute "Pedro Kourí",
days. Havana;
2
Epidemiology Dept., Provincial Center of Hygiene, Epidemiology
and Microbiology, Santiago de Cuba, Cuba
P010
Introduction: Current dengue control strategies mainly comprise dis-
WHO FAILED TO MEET TO ELIGIBILITY CRITERIA IN A VACCINE persed and irregular control actions that are reactive to detected clinical
TRIAL IN NORTHERN SIERRA LEONE, AND WHY? ANALYSIS OF cases and/or massive insecticide application to mitigate outbreaks. In
DATA FROM THE EBOVAC-SALONE STUDY Santiago de Cuba we implement control strategies based on risk strati-
fication at city level in order to concentrate pro-active, sustained efforts
Baiden F.1,2 , Ishola D.1,2 , Kowuor D.1,2 , Afolabi M.1,2 , Owusu-Kyei in high transmission risk areas.
K.1,2 , Lowe B.2 , Kohn B.1,2 , Otieno T.1,2 , Manno D.2 , Samai M.1,3 , Aims: To describe dengue outbreak occurred between 2010 and 2018 in
Leigh B.1,3 , Greenwood B.2 , Watson-Jones D.2,4 Santiago de Cuba and the changes on epidemiological pattern associated
1
EBOVAC-Salone Project. Kambia, Kambia District, Sierra Leone; to interventions addressing hotspot.
2 Methodology: We use SIR; Richards model for modeling dengue trans-
London School of Hygiene and Tropical Medicine, London, UK;
3
College of Medicine and Allied Health Sciences, Freetown, Sierra mission. We introduce mobility of humans between neighboring areas
Leone; into a mathematical model.
4
Mwanza Intervention Trials Unit, Mwanza, Tanzania Results: The series of weekly reported cases show that instead of a
single wave associated with the rainy season, on average, a long wave
Introduction: The EBOVAC-Salone trial in Kambia, district northern Sierra of cases starting in statistical week 33 (summer) last to week 10 of
Leone is a phase 2/3 safety and immunogenicity trial of the the next year. Despite the persistence of seasonal patterns, our analysis
Ad26.ZEBOV, MVA-BN-Filo 2 dose Ebola vaccine regimen developed by also shows that the areas where the new strategy was implemented,
Janssen. Strict eligibility criteria were applied to screen and enroll adults outbreaks parameters (basic reproduction number, outbreak size and
and children > 1 yr. We applied adapted laboratory normal ranges and peak epidemic size) decrease faster than in the areas with the standard
determined malnutrition using WHO/CDC growth charts. control measures.
Aim: To describe the characteristics of participants who did not meet Conclusion: Targeting control strategies in areas at high risk for dengue
eligibility criteria and the reasons why. transmission could change the epidemiological pattern of dengue trans-
Methods: A participant who underwent screening but was not enrolled mission and reduce the outbreak impact.
was considered to have failed screening (screen-failures). We extracted
data on screen-failures at all three clinics (two sub-urban and one
rural) and performed analysis to describe their sociodemographic P014
characteristics. We ran frequencies to detail reasons for failures and
A HANG-UP AND BEHAVIOUR CHANGE COMMUNICATION CAM-
performed statistical analysis to explore the effect of sex, age and clinic
location. PAIGN TO IMPROVE BED NET USE: A PILOT STUDY FROM THE
Results: A total of 556 (33%) out of 1,630 (65% males) potential LOCALITY OF BARÉ - BAKEM IN CAMEROON
participants aged >1-year failed screening. The majority, 344 (63%) Bekolo C.E., D’Arcy T.
were males. The major causes were out-of-range (abnormal) laboratory University of Dschang, Dschang, Cameroon
parameter(s) (mostly haemoglobinPoster Presentations
behaviour change communication (BCC) campaign could improve bed net Bhattarai S.1 , Rijal A.2 , Marahatta S.2 , Khadka A.1
use in a rural population of Baré in Cameroon. 1
Dept. of Dermatology and Venreology, Kathmandu Medical Col-
Methods: We conducted a four-day campaign comprised of a door-to- lege, Kathmandu;
door hang up of unhung LLINs and a BCC on bed net use in April 2017 2
Dept. of Dermatology and Venreology, B.P.Koirala Institute of
in the Peace Corps Volunteer Community of Baré. Sleeping under a bed Health Sciences, Dharan, Nepal
net the previous night was used as the indicator for bed net use. A two-
sample proportional test was used to determine the difference in bed net Introduction: Leprosy is a chronic granulomatous immune response to
hang-up and use before and after the campaign. infection of the skin and the nerves with mycobacterium leprae. Though,
Results: A total of 6879 persons from 1414 households in all the 13 Leprosy has been eliminated from developed countries, it is still consid-
neighbourhoods and villages were reached by 26 volunteers. The number ered to be a major public health problem in developing countries of Africa,
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of LLINs still remaining one year after the distribution of 4255 LLINs was Asia and Latin America. Declaration of elimination of leprosy as a public
2959 (70%) of which 1032 (35%) were still unhung. During the campaign, health problem in Nepal was done on the 19th of January 2010 but the
a total of 435 additional LLINs were hung up at a cost estimated at less disease prevalence is still high in endemic regions.
than US$1 per LLIN. The overall bed net hang-up rate rose from 65% Aim: To estimate the number of cases visiting a tertiary care centre in
(95%CI: 57% - 74%) before the campaign to 80% (95%CI: 71% - 89%) Eastern and Central Nepal after the declaration of the elimination.
after the campaign (p = 0.02). Bed net use increased from 75% (95%CI: Methods: All clinically diagnosed and newly registered cases of leprosy
65% - 86%) before the campaign to 92% (95%CI: 86% - 99%) after the attending Dermatology Department of BPKIHS and KMCTH were prospec-
campaign (p = 0.009). tively included in the study (2010-2018). A detailed history, cutaneous
Conclusion: This small-scale dual intervention of LLIN hang up and BCC and nerve examination were performed and recorded in a pre set pro-
could be a useful tool to improve bed net use by scaling up bed net forma.
hang up. We recommend a more robust methodology applied on a larger Results: A total of 544 new cases where seen in the dermatology OPD
population size to determine the effectiveness of this campaign. with a male preponderance of 363/544 (66.7%). The patients were
more in the 20-29 years age group. 495/544(90.9%) patients presented
with skin lesions while 410/544(75.36%) of the patients had only nerve
P015 involvement.
Reactions were seen in 379/544(69.6%) patients and disabilities were
THE TICK CELL BIOBANK: TICK AND OTHER ARTHROPOD CELL seen in 251/544(46.1%) patients. Multibacillary treatment was started
LINES FOR TROPICAL MEDICINE RESEARCH in 392/544 (72.0%) patients and Paucibaciallary in 152/544(27.9%)
Bell-Sakyi L.1 , Al-Khafaji A.1 , Hartley C.1 , Darby A.2 , Baylis M.3,4 , patients after the clinical, bacteriological and histological co-relation.
Conclusion: The current reality is that there is a need to sustain and
Makepeace B.L.1
1 provide quality leprosy services to all persons through general health
Dept. of Infection Biology, Institute of Infection and Global system, including a good referral system. Efforts need to be made to
Health, University of Liverpool; reduce deformity through early detection, self care, physiotherapy and
2
Institute of Integrative Biology, University of Liverpool; reconstructive surgery and developing sound surveillance systems. Con-
3
Dept. of Epidemiology and Population Health, Institute of Infec- stant evaluation, monitoring and case detection should be still pursued
tion and Global Health, University of Liverpool; actively in endemic districts. Health Education activities and involvement
4 of teaching hospitals and trained health specialist at the tertiary general
NIHR Health Protection Research Institute in Emerging and
Zoonotic Infections, Institute of Infection and Global Health, health care delivery system would further help in sustaining the national
University of Liverpool, Liverpool, UK goal of elimination.
Continuous cell lines derived from ticks and other arthropods are essen-
tial tools for laboratory-based research on medically-important, vector- P017
borne viruses, bacteria, protozoa and helminths. The Tick Cell Biobank
(TCB) at the University of Liverpool, the world’s only dedicated repository REDUCED PLASMA CONCENTRATIONS OF VITAMIN B6 AND
for tick and other arthropod cell lines, underpins this research through INCREASED PLASMA CONCENTRATIONS OF THE NEUROTOXIN
provision of existing cell lines and training in their maintenance to scien- 3-HYDROXYKYNURENINE ARE ASSOCIATED WITH NODDING
tists worldwide, and generation and characterisation of novel cell lines. SYNDROME: A CASE CONTROL STUDY IN GULU AND AMURU
As well as housing the world’s largest collection of tick cell lines, the
DISTRICTS, NORTHERN UGANDA
TCB is working to generate new cell lines from biting midges, sand flies,
tsetse flies, mosquitoes and mites. The burden of vector-borne disease Obol J.H.1 , Arony D.A.2 , Wanyama R.3 , Luryama Moi K.2 , Bodo
falls disproportionately on lower- and middle-income countries (LMIC) B.4 , Odong P.O.5 , Odida M.6
in the Tropics, and the TCB’s emphasis on tropical arthropod vectors 1
Dept. of Public Health, Gulu University;
reflects this; to facilitate dissemination and uptake of arthropod cell 2
line technologies by LMIC scientists, the TCB is establishing Outposts in Dept. Microbiology and Immunology, Gulu University;
3
Malaysia, Kenya and Brazil. Recent applications of tick cell lines in tropical Medical Biochemistry, Gulu University;
4
medicine research include development of the first in vitro culture system Paediatrics and Child Health, Gulu University;
5
for propagation of Mycobacterium leprae, and advances in understanding District Health Office, Amuru District Local Government, Amuru,
of tick-human transmission of Crimean-Congo hemorrhagic fever virus, Uganda;
tick-borne flaviviruses and spotted fever group Rickettsia species. 6
Dept. of Pathology, Makerere University, Kampala, Uganda
Introduction: Nodding syndrome is a rare disease whose onset of symp-
P016 toms in affected children is marked by the development of nodding head
movements, which are reported to be provoked either by the sight of food
LEPROSY AFTER THE ELIMINATION: NEPAL EXPERIENCE FROM or exposure to cold weather. The nodding head movements have been
THE UNIVERSITY TEACHING HOSPITALS documented to correspond with the onset of subclinical brain seizure
S102Transactions of the Royal Society of Tropical Medicine and Hygiene
activity on electroencephalography. The disease has been demonstrated experts/techniques about: (i) identification, managing and reduction of
to progress cognitive impairment, stunting, lip changes and other physical larvae breeding sites, (ii) early detection of larvae and mosquitoes and
deformities, mental retardation, behavioural disabilities and malnutrition. (iii) vector control measures. A communication channel will be created
Nodding syndrome was first reported in Uganda in 2003 among internally to exchange information between the hotel entities and the local public
displaced populations. The risk factors for nodding syndrome in Uganda health authorities.
largely remains unknown. Results: We expect to nominate and train at least one focal point at each
Aims: The aim of the study was to explore and determine the association hotel identified. With this intervention, we expect to reduce breeding sites
of vitamin B6 deficiency and the resulting high 3-hydroxykynurenine (3- at hotels and the risk of mosquitoes’ proliferation.
HK) levels and nodding syndrome as well as other risk factors among Conclusion: We expect that promoting partnerships and intersectoral
children with nodding syndrome in Northern Uganda. collaborations between hotel sector and local health services could
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Methods: Case-control study conducted in Gulu and Amuru districts. strengthen the surveillance of these species.
Cases were children/young adults with nodding syndrome. Healthy chil-
dren/young adults were recruited as controls from same community as
cases. Data on socio-demographic and other risk factors was collected P021
using questionnaires. Whole blood was collected in EDTA tubes for assay
of 3-HK and vitamin B6 using sandwich ELISA. Conditional logistic regres- KNOWLEDGE AND PREVENTIVE ATTITUDES ON VISCERAL
sion model was used to assess associations. LEISHMANIASIS AMONG BRAZILIAN DOG OWNERS: REPORT
Results: 66 cases and 73 controls were studied. Factors associated with FROM A HOUSEHOLD SURVEY
nodding syndrome were being positive for 3-HK (AOR=4.50, p=0.013),
vitamin B6 concentration below mean (AOR=7.22, P=0.001), child being Carvalho A.G.1,2 , Luz J.G.G.1,2 , Rodrigues L.D.2 , Dias J.V.L.3 ,
taken care of by mother only (AOR=5.43, p=0.011), child being taken care Fontes C.J.F.1
of by guardian (AOR=5.90, p=0.019) and child consuming relief food at 1
Post-Graduation Program in Health Sciences, Federal University of
weaning (AOR=4.05, p=0.021).
Conclusion: Having low vitamin B6 concentration which leads to a build Mato Grosso, Cuiabáil;
2
p of 3-hydroxykynurenine concentration in cases as a main risk factor. School of Medicine, Federal University of Mato Grosso, Ron-
Therefore, cases should be treated with vitamin B6 and community mem- donópolis;
3
bers should be sensitise to ensure adequate dietary intake of vitamin School of Medicine, Federal University of Jequitinhonha and
B6 so that the risk of nodding syndrome among children is averted. Mucuri Valleys, Teófilo Otoni, Brazil
We encourage future prospective intervention study to be conducted
to assess the effect of low vitamin B6 on the development of nodding Introduction: In Brazil, visceral leishmaniasis (VL) represents a zoonosis
syndrome via raised 3-HK concentration. caused by the protozoan Leishmania (Leishmania) infantum. Dogs are the
main domestic animal reservoir. At present, VL is expanding geographi-
cally through the Brazilian territory, and 3,500 new cases on average are
P020 annually reported. The adopted control measures are proving to be inef-
ficient, despite of the high costs involved. Thus, it is important to assess
HOTEL SECTOR ENGAGEMENT FOR LARVAE AND MOSQUITO the popular knowledge, attitudes, and practices on VL to identify the
SURVEILLANCE IN ALGARVE REGION, PORTUGAL: THE MOSK.O. gaps that should be targeted to drive appropriate, lasting, and effective
INTERVENTION PROTOCOL interventions.
Aim: To describe the knowledge and preventive attitudes concerning
Cancela M.1 , Bodião J.1 , Guerreiro N.2 , Guerreiro A.C.2 visceral leishmaniasis (VL) among dog owners from a Brazilian hyperen-
1 demic area (Rondonópolis, Mato Grosso State).
Public Health Unit, Primary Health Care Unit Grouping Algarve I -
Central; Methods: Data were collected between October 2016 and February 2017
2
Dept. of Public Health and Planning, Algarve Regional Health during a household survey. A total of 405 dog owners were interviewed
Administration, Faro, Portugal based on a semi-structured questionnaire.
Results: Most of the interviewees (95.6%) had previously heard about
Introduction: Aedes albopictus mosquito, also known as Asian tiger VL. However, only 27% were aware of the clinical manifestations of
mosquito, is one of the most invasive species in the world and a vec- the human disease. Fever, skin lesions, and abdominal distention were
tor of several diseases like dengue, chikungunya and others. Albopictus predominantly cited. In contrast, 65.4% were aware of the signs of
is a container-inhabiting specie that can be found in urban or rural canine VL (CVL), especially onychogryphosis, skin lesions, and alopecia.
environments, both public and private areas with vegetation, occupied Although 59.3% considered VL to be a vector-borne disease, the major-
by humans or animals. Cities and large towns are good environments ity did not know the vector’s name (94.6%) and could not identify it
for sustainable mosquito larval control since mosquito breeding sites (93.1%). Household spraying of insecticides on their own account or
are well-defined and easily located. The most effective way to prevent by public health agencies was reported by 65.4% and 17.8% of the
Albopitus dissemination is reducing breeding sites. This specie was first respondents, respectively. The use of topical repellents (17.5%) and use
introduced in mainland Portugal in Penafiel and Algarve region in 2017. of bed net/window screen (1.75%) were considered as unusual practices.
In the summer of 2018, it has been detected again in a peri-urban area Previous ownership and treatment of a dog with CVL was reported by
and in an hotel both in Algarve Region. None of the captured mosquitoes 23.5% and 13.6% of the respondents, respectively. The reasons behind
were infected. euthanasia recommendations for infected dogs were unknown by 34.8%
Aim: This project aims to reduce breeding sites and the early detection of of the participants, and 69.7% reported that they would consent for
mosquitoes. euthanasia if their dog was infected. A small proportion of dogs were
Methods: We identified around seventy-two hotels in Loulé county with previously tested for CVL (13.3%), vaccinated against CVL (1.5%), and
similar microclimates which are favorable for Aedes Albopictus prolifera- wore insecticide-impregnated collars (13.8%).
tion. One garden maintenance worker in each hotel who will serve as focal Conclusion: The lack of awareness and misconceptions about VL and
point will be nominated and will receive theoretical and practical train- its prevention was observed, which emphasizes the need for health
ing lead by a Public Health medical resident and Environmental Health education.
S103Poster Presentations
P022 6
Kothari Medical Centre, Kolkata-700027, West Bengal, India;
7
PREVALENCE AND ASSOCIATED FACTORS OF SOIL- Dept. of Epidemiology, UCSF School of Medicine, San Francisco,
TRANSMITTED HELMINTH AND FOOD-BORNE TREMATODE USA;
8
INFECTIONS IN RURAL THAILAND: MULTILEVEL ANALYSIS Dept. of Public Health, Institute of Tropical Medicine, Antwerp,
USING BAYESIAN HIERARCHICAL REGRESSION MODELING Belgium;
9
Dept. of Biology, Asian University for Women, Chittatong,
Charoensakulchai S.1 , Suwannahitatorn P.2 Bangladesh
1
Fifth year medical student, Phramongkutklao College of Medicine;
2
Dept. of Parasitology, Phramongkutklao College of Medicine, Background: Visceral leishmaniasis (VL) is a parasitic disease, transmit-
ted by the sand fly species Phlebotomus argentipes in the Indian sub-
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Bangkok, Thailand
continent. We evaluated the effect of long-lasting insecticide treated
Introduction: Cultures and ways of life bring rural Thai populations bed-nets (LLIN) and bed-nets impregnated with slow-release insecticide
into close contact with soil-transmitted helminth (STH) and food-borne tablet K-OTAB 1-2-3 (jointly insecticide-treated nets or ITN) on VL inci-
trematode (FBT) infections. Associated factors and estimation of at-risk dence in a highly endemic sub-district (upazila) in Bangladesh.
areas of infections are not widely studied in Thailand. Aim: We aimed to assess the effect of LLIN/ITN on VL incidence in the
Aims: Identify associated factors and estimate at-risk areas for interven- endemic communities.
tion. Methods: Several distributions of LLIN or K-OTAB 1-2-3 for self-
Methods: Cross-sectional study was conducted in 2017 using stool exam- impregnation of bed-nets at home took place in Fulbaria upazila,
ination and questionnaires in 6 villages of Phra-ploeng District, Sa-Kaeo Mymensigh district from 2004-2008 under three research projects. We
Province, eastern Thailand. Stool specimen were prepared with simple included all households (n=8142) in the 20 villages that had benefited
smear, Kato-Katz and formalin-ethyl concentration technique. Village- in the past from one of these interventions in the “exposed cohort”. We
level and individual risk for acquiring the infection was evaluated using recruited a “non-exposed cohort” in villages with contemporaneously
Bayesian hierarchical regression modeling with posterior estimation from similar incidence rates who had not received such vector control
MCMC sampling. Village-level risk was determined as probability of having interventions (7729 HHs from nine villages). In both cohorts, we visited
OR > 1 in each village. all families house-to-house and ascertained any VL cases for the 3-year
Results: From 1267 enrolled participants, highest prevalence of STH and period before and after the intervention. We evaluated the incidence rate
FBT infection was Strongyloides stercoralis (SS) and Opisthorchis viverrini (IR) of VL in both cohorts as primary endpoint, applying the difference-
(OV): 3.8 % and 8.4%, respectively. For SS infection, male gender and in-differences method. We also interviewed households about the
hookworm coinfection increased risk of infection. Prevalence of hook- acceptability and durability of the ITN intervention.
worm infection was 1.3% and increased risk of SS infection with OR = Results: The study identified 1011 VL cases (IR 140.47/10,000 per year
11.3 (2.4-30.6, 95% credible interval). For OV infection, male gender and [py]) before the intervention, of which 534 and 477 cases in the inter-
consumption of Koi pla (local instantly prepared freshwater fish menu) vention and control areas respectively. The IR was 144.13/10,000 py
increased risk of infection. Increasing age increased risk of infection for and 136.59/10,000 py in the intervention and control areas respectively,
both SS and OV. For village-level risk, probability of having higher risk for with no significant difference before the intervention. After the inter-
SS infection ranged 22.3 – 73.0% and for OV infection ranged 42.4-58.2%, vention, 555 cases (IR 77.11/10,000 py) were identified of which 178
in 6 villages. (IR 48.04/10,000 py) in the intervention and 377 (107.95/10,000 py) in
Conclusion: Male gender and increasing age increase risk of infection the control area. The intervention area had a significant lower IR than
for SS and OV. Therefore, hygiene and consumption behaviors should be the control area during follow up, rate difference = –59.91, pTransactions of the Royal Society of Tropical Medicine and Hygiene
Background: Visceral Leishmaniasis (VL), is a deadly disease, transmitted The L1014F kdr allele was significantly associated with mosquito
by the sand fly, Phlebotomus argentipes in the Indian sub-continent. survival following deltamethrin or permethrin treatment (p=0.003 and
In 2005, the governments of Bangladesh, India and Nepal signed a p=0.04, respectively). N1575Y and I1527T mutations were identified
Memorandum of Understanding to eliminate the disease by 2015, a in 13% and 10% of individuals, respectively, but neither conferred
deadline which was later extended to 2017. Bangladesh achieved the increased pyrethroid tolerance. Partial restoration of pyrethroid sus-
target in 2017, but in order to get the elimination certificate from the ceptibility following synergist pre-exposure suggest a role for mixed-
World Health Organization, this target needs to be sustained for at least function oxidases. Carbamate resistance was lower and significantly
three consecutive years. Active community participation will be essential associated with the G119S Ace-1 mutation (p=0.001). Oocyst rates
if this success is to be maintained for a longer period of time. were 6.8% and 4.2% among resistant and susceptible mosquitoes,
Aim: We aimed to assess the current knowledge, attitudes and practices respectively; survivors of bendiocarb exposure were significantly more
Downloaded from https://academic.oup.com/trstmh/article/113/Supplement_1/S99/5569917 by guest on 12 March 2022
on kala-azar. likely to be infected (p=0.03). Resistant mosquitoes had significantly
Methods: A community-based cross-sectional study was conducted in lower parity rates; however, a subset of intensely pyrethroid-resistant
two endemic upazilas (sub-districts), Fulbaria and Trishal. Based on the vectors were more likely to be parous (p=0.042 and p=0.045, for
Upazila Health Complex (UHC) surveillance data, one endemic village was survivors of five and ten times the diagnostic dose of insecticides,
randomly selected from each of these upazilas. Total 511 households respectively). Our findings emphasize the need for additional studies
(HHs) [261 in Fulbaria and 250 in Trishal] were included in the study. An directly assessing the influence of insecticide resistance on mosquito
adult household was interviewed using a structured questionnaire. fitness.
Results: We found 53% respondents were illiterate and 78.86% houses
were made of tin. 36.79% HHs had cattle sheds and 75.00% were
within 20 feet distance from the living area. All participants had heard P026
about kala-azar. 30.14% of HHs or neighboring HHs have/had kala-azar
patients during past years. About 69% respondents knew that kala-azar SEROPREVALENCE OF VACCINE-PREVENTABLE DISEASES IN
is transmitted through sick persons. More than 39% participants said that YOUNG AFRICAN MIGRANTS RECENTLY ARRIVED TO MADRID,
mosquitoes transmitted kala-azar, but about 91% informed that they SPAIN
had heard of sand flies. About 47% participants were aware that this
vector laid their eggs in the water. Less than 60% of respondents had a Comeche B., Chamorro-Tojeiro S., Pérez-Molina J.A., Norman F.,
fairly good knowledge on kala-azar. 88.14% people prefers to visit UHC for Monge-Maillo B., López-Vélez R.
treatment. We found 65.95% participants have good attitudes. More than National Referral Unit for Tropical Diseases, Infectious Diseases
62% of people used bed nets for preventing sand fly bites and 96.48% Dept.,Ramón y Cajal University Hospital, Madrid, Spain
families had mosquito nets. More than 50% participants showed good
practices on kala-azar. Introduction: The vaccination coverage in the migrants is poorer in
Conclusion: Overall the community is well aware of kala-azar but national comparison with the native population. Seroprevalence studies of vaccine
programme should not stop their current community sensitization activ- preventable-diseases in newly arrived immigrants would be essential
ities, since a halt in the efforts might undo all the progress made so far. before designing a specific vaccination program in this collective.
Aim: Check the vaccination coverage of the newly arrived African immi-
grants.
P025 Methods: Retrospective study of seroprevalence in young African
migrants, new arrivals (>16 years old), who attended in a referral centre
INVESTIGATING THE RELATIONSHIP BETWEEN INSECTICIDE in Madrid, Spain, from November 2017 to November 2018. The following
RESISTANCE, UNDERLYING MOLECULAR MECHANISMS AND serological determinations were performed: HBV, HAV, measles, rubella,
MALARIA PREVALENCE IN ANOPHELES GAMBIAE S.L FROM mumps and varicella. Migrants susceptible to any of these diseases were
GUINEA subsequently referred for immunization.
Results: 79 migrants from 14 different African countries were included.
Collins E.L.1 , Vaselli N.M.1 , Sylla M.2 , Beavogui A.H., Osborne J.1 , Most of them were from West Africa: 25 (31%) from Republic of Guinea,
Lawrence G.3 , Irish S.3,4 , Walker T.1 , Messenger L.A.3, 5 14 (18%) from Cameroon and 9 (11%) from Ivory Coast. Mean age was
1
Dept. of Disease Control, Faculty of Infectious Tropical Diseases, 26 years (SD 7.9) and 73 (92%) were males. Immunity for rubella was
London School of Hygiene and Tropical Medicine, London, UK; detected in 75 (95%), for HAV in 75 (95%), for measles in 72 (91%), for
2
Centre National de Formation et de Recherche en Santé Rurale de varicella in 70 (89%), for mumps in 65 (82%), and for HBV in 42 (53%).
Guineans were the best immunized although no significant differences
Maferinyah, Maferinyah, Guinea;
3 were found among countries. Of mention is that only 50% of women (all
Entomology Branch, Division of Parasitic Diseases and Malaria, of them in childbearing age) had rubella immunity.
Center for Global Health, Centers for Disease Control and Preven- Conclusion: 1. In our study, vaccine-preventable diseases coverage is
tion, Atlanta; similar to those officially reported from these countries to the WHO
4
President’s Malaria Initiative, Bureau for Global Health, Office of reflecting accuracy in reporting data. 2. Although the measles immunity
Infectious Disease, United States Agency for International Devel- rate is high, it does not reach the 95% established by the European
opment, Washington DC; Vaccine Action Plan for measles elimination. 3. The low proportion of
5
American Society for Microbiology, Washington DC, USA immune women of childbearing age against rubella makes necessary the
screening of this disease and the implementation of active measures for
The threat of insecticide resistance across sub-Saharan Africa is their immunization.
anticipated to severely impact the continued effectiveness of malaria
vector control. We investigated the effect of carbamate and pyrethroid
resistance on Anopheles gambiae s.l age, Plasmodium falciparum P028
infection and characterized molecular resistance mechanisms in
Guinea. Pyrethroid resistance was intense, with survivors of ten times SUSTAINABLE CONTAINMENT OF DENGUE OUTBREAKS
the insecticidal concentration required to kill susceptible individuals. THROUGH COMPREHENSIVE INTEGRATED APPROACH
S105Poster Presentations
Dheerasinghe D.S.A.F.1 , Samaraweera P.C.1 , Cader M.2 , district of Tandjoaré recorded low vaccination coverage following the end
Rajapakshe O.B.W.1 , Abeysekara I.1 , Weerasinghe W.M.I.P.1 , of GAVI fund.
Rathnayake R.M.T.D.1 , Kodithuwakku K.A.L.C.1 , Pannila Aim: The aim of our study was to describe the indicators for implementing
Hetti N.1 , Tissera H.A.1,3 the RED approach.
1
National Dengue Control Unit of the Ministry of Health; Methods: A cross-sectional study was done based on interviews with 18
2 managers of the Expanded Program on Immunization (EPI) of health-
National Programme for Tuberculosis Control and Chest Diseases
care facilities (HCFs) and 70 community leaders. All healthcare facilities
of Ministry of Health; offering vaccination services in the district were included in our study.
3
Epidemiology Unit of the Ministry of Health, Sri Lanka The analysis of the results was based on the WHO indicators of the RED
Introduction: Dengue is a major public health problem in Sri Lanka approach.
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where the entire country and all ages are affected due to high disease Results: Among healthcare facilities, 17% had microplanning documents
transmission. for immunization activities for the current year. Less than a quarter of
Aim: The aim of the programme is to carry out proactive integrated vector healthcare facilities were on schedule for routine immunization sessions.
management led by source-reduction campaigns based on real-time Only one healthcare facility had properly completed and updated vaccine
web-based epidemiological and entomological surveillance data, along and consumable stock management sheets. None of the healthcare
with the participation of all stakeholders. facilities have received external funding for the implementation of the
Methods: There has been great progress in disease and entomological RED approach. Among HCFs surveyed, less than half carried out advanced
surveillance, clinical management, and active engagement of various strategies and 11% vaccinated at least once a week. Community partic-
ministries through the Presidential Task Force (PTF) on Dengue Prevention. ipation in the microplanning process was 44% according to EPI officers
Accordingly, guidelines for Aedes vector surveillance and control was and 26% according to community leaders. No supportive supervision
developed by the National Dengue Control Unit to streamline the inte- visits were received by the HCFs surveyed. Among HCFs, less than a
grated vector management strategies throughout the country. quarter had up-to-dated, plotted self-monitoring diagrams. None of the
Regional Epidemiologists, Medical Officers of Health, Entomologists and EPI managers were able to provide accurate information on the 5 com-
Health Entomological Officers, and Public Health Inspectors were trained ponents of the RED approach.
on vector surveillance and vector control at National level in 2017. Conclusion: Our study shows that the RED approach is not sufficiently
Special Mosquito Control Campaigns (SMCCs) for source reduction, with implemented in the Tandjoaré district,Togo when GAVI funding stops. An
the participation of stakeholders especially Tri-Forces, were conducted in appropriation by the HCFs of this approach constitutes a way of improving
2017 and 2018 covering 2.7 million and 1.4million premises respectively. vaccination coverage.
To improve the clinical management of Dengue, in-service training pro-
grammes were conducted (35 and 14 programmes in 2017 and 2018
respectively) for consultants, medical officers, nursing officers in high-risk P031
districts by the local experts. Further, capacities of high dependency units PERMETHRIN RESISTANT BED BUGS (CIMEX LECTULARIUS) CAN
were strengthened.
BE KILLED BY A COMBINATION OF H2O2 FLUID AND PERME-
The PTF was reactivated in 2017 with the participation of relevant stake-
holders, to obtain maximum support. Up to now, 24 PTF meetings have THRIN – A SYNERGISTIC EFFECT AS A LIGHT AT THE END OF
been conducted to assess the progress of Dengue prevention and control THE TUNNEL
activities and containment of outbreaks. Duscher G.G.1 , Hodžić A.1 , Battisti E.2 , Boigenzahn S.3 , Schwan
Results: During SMCCs conducted in 2017 and 2018, Health care workers
T.3 , Jaeger P.3 , Ljuhar D.3
along with the Tri-Forces found 20% and 21% potential breeding places 1
and 1.98% and 2.29% positive breeding places in the respective years. Institute of Parasitology, University of Veterinary Medicine,
With all these efforts, there is a reduction of annual incidence of Dengue Vienna, Austria;
2
from 865.9 to 239.8 per 100,000 population (in 2017 and 2018 respec- Università degli Studi di Torino, Turin, Italy;
3
tively) and case fatality rates have been halved from 0.24% in 2017 to Braincon Technologies, Vienna, Austria
0.11% in 2018.
Introduction: Due to traveling habits of the people as well as the trans-
Conclusion: It is found that an integrated approach is an effective
portation of goods bed bugs emerged all over the world and became an
method in sustaining low endemicity and curtailing outbreaks in
increasing pest all over the world. Those bugs can be found in hotels,
resource-poor settings.
hostels and cabins and is not limited to poverty. Bed bugs feed on
humans at night and may cause wheals, redness and pruritus and as
consequence of the nightly visits insomnia and anxiety state. Until now
P030
there is no confirmed vector role for the bed bugs, but experimentally the
IMMUNIZATION APPROACH "REACH EVERY DISTRICT" WHEN can transmit some pathogens e.g. Trypanosoma cruzi.
GAVI FUNDING STOPS IN TANDJOARE, TOGO Aim: Countermeasures in the past led to selection for resistant bugs,
including resistant against pyrethroids. Therefor we tested permethrin
Djanda L.1 , Kassankogno Y.2 , Boko A.K.1 , Lacle A.1 , Thonneau resistant and non-resistant bed bugs with a special combination of H2O2
P.3 and permethrin.
1
Dept. of Immunization, Lomé, Togo; Methods: Bed bugs were exposed to a mixture of permethrin and
2
Faculties of Health Sciences, University of Lomé, Togo; H2O2, permethrin alone and H2O2 alone by the use of a modified
3
Senghor University in Alexandria, Egypt fogger (droplet size ∼ 1 μm). On the molecular level we investigated
the expression of mRNA of several detoxification enzymes from the
Introduction: The objective of "Reach Every District" (RED) approach groups cytochrome P450 monooxygenases, glutathione-S-transferases
was to ensure sustainable and equitable vaccination coverage for every and carboxylesterases by the use of RT-qPCR.
woman and child in every community. According to the World Health Results: The mixture (permethrin and H2O2) performed best during the
Organization, RED has proven its impact on improving vaccinal coverage viability study as well as during the detoxification studies. This might
in developed countries between the years 2000 and 2011. The health be due to a synergetic effect of the compounds. After exposure with
S106Transactions of the Royal Society of Tropical Medicine and Hygiene
3
permethrin the oxidative stress increases and additionally O2 radicals are Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz,
applied. Ministério da Saúde, Salvador, Brazil;
Conclusion: This are first promising results, but other strains of bed bugs 4
Dept. of Epidemiology of Microbial Diseases, School of Public
have to be tested to confirm the success of this treatment. Health, Yale University, New Haven, USA
Introduction: Leptospirosis is a zoonotic disease which causes over a
P034 million human cases annually. Exposure to Leptospira bacteria is high
in urban slum conditions with a significant proportion testing positive
VIDEO-ENHANCED WHO CONE TESTS: DETAILED INSIGHTS for leptospiral antibodies, making it difficult to identify recent subclinical
FROM A 3-MINUTE TEST infections in these populations. The gold standard diagnostic for detect-
Downloaded from https://academic.oup.com/trstmh/article/113/Supplement_1/S99/5569917 by guest on 12 March 2022
ing leptospiral infection is the microscopic agglutination test (MAT). Rein-
Emery M., Matope A., Gleave K., Hughes A., Steen K., Foster G., fection is usually defined serologically by a defined threshold (antibody
Jones J., McCall P.J. titre ≥ 800) or an increase in titre relative to a previous measure (normally
Dept. of Vector Biology, Liverpool School of Tropical Medicine, a four-fold increase in titre). However, these definitions do not take into
Liverpool, UK account the immune response of an individual over time, which can be
modelled as an initial titre rise on infection and subsequent decay over
WHO-cone bioassay tests are used to evaluate the toxicity of insecticide-
the following years. This can result in reinfections between follow-ups not
treated bednets and other impregnated textiles against malaria
being detected.
mosquitoes. They are a standard component in the screening pipeline
Aim: To characterise agglutinating antibody titre rise and decay in
for evaluating novel insecticidal treatments for use on bednets, a
human leptospirosis cases and evaluate its use in the detection of
search that has become a global priority with the urgent need for
reinfections.
new insecticides that do not share resistance mechanisms with
Methods: To estimate the minimum follow-up time required to be able
pyrethroids.
to detect reinfections, antibody response data was simulated for a range
A simple three-minute procedure, the cone bioassay, provides data on
of titre rise and decay parameter values with infection events modelled
knockdown and mortality at various times post-exposure but has two
as a Poisson process. A statistical model was then fitted to data from
important limitations. First, the actual time a mosquito spends in contact
longitudinal serological cohort surveys to estimate these parameters.
with the test netting may be significantly less than the 3 minutes of
Data sources for this analysis were an ongoing longitudinal serological
‘exposure’ time, particularly if the net treatment has repellent properties;
cohort study in Salvador, Brazil and three historical studies from Barba-
this could significantly underestimate a net’s lethality. Secondly, in the
dos, Italy and São Paolo, Brazil. This final model was then applied to a
absence of an attractive host on the other side, a treated net’s repellent
long-term biannual serological cohort study in Salvador (2013-2019) to
properties might be relatively high, further increasing the underestima-
detect reinfections.
tion of its actual impact.
Results: This is an ongoing study which will report on the relationship
To permit more accurate measurement of the effects of insecticidal
between follow-up time and titre rise and decay parameters, and will
netting, and also in an attempt to reveal additional information on
estimate these parameters, accounting for differences in age, sex and
behavioural effects (e.g. contact-irritancy vs. spatial repellency) we used
population leptospirosis prevalence. It will compare the number of rein-
a basic smartphone camera to record mosquito activity during the cone
fections detected by the model with current definitions.
bioassay for subsequent analysis.
Conclusion: This study will provide important information about the
The WHO standard cones and the net substrate being tested are mounted
immune response to leptospiral infection in humans and a new tool
on a custom fabricated acrylic bioassay rig. Five anopheline female
for identifying reinfection from longitudinal serological survey data. This
mosquitoes are tested for three minutes, with or without a human
will be valuable for epidemiological research, in particular identifying key
attractant (no blood feeding). Videos are analysed by scan sampling at
routes of transmission and vulnerable subpopulations.
five second intervals to quantify numbers of mosquitoes in contact with
the net, the cone or in free flight. We developed custom software to
analyse video frames every 0.1s to detect moving mosquitoes within
the cone. Thus, mosquito movement is recorded and categorised into P037
four cone regions. Individual video frames are aggregated sequentially to
generate a composite image of the total collective behavioural response. DIFFERENTIAL BEHAVIOR IN TRANSCRIPTOMIC AND PRO-
Using data from a range of current and next generation bednets, we will TEOMIC PROFILES OF Leishmania mexicana ISOLATES:
report on the video cone test’s performance compared with other test TARGETS FOR DIAGNOSIS?
methods, and its potential to complement the WHO cone bioassay at
minimal cost. Fernández-Figueroa E.A.1 , Muñoz-Montero S.A.1 , Imaz-
Rosshandler I.2 , Becker-Fauser I.3 , Miranda-Ortíz H.4 ,
Cervantes-Sarabia R.3 , Alanis-Funes G.5 , Rangel-Escareño C.1
P036 1
Computational Genomics Dept. National Institute of Genomic
Medicine, Mexico City, Mexico;
IMPROVING DETECTION OF RECENT SUBCLINICAL LEPTOSPI- 2
DAMTP, Centre for Mathematical Sciences, University of Cam-
RAL INFECTIONS IN HIGH PREVALENCE COMMUNITIES: MOD-
bridge, Cambridge, UK;
ELLING THE MICROSCOPIC AGGLUTINATION TEST (MAT) TITRE 3
Unidad de Investigación en Medicina Experimental, Centro de
DECAY
Medicina Tropical, Facultad de Medicina, Universidad Nacional
Eyre M.1 , Giorgi E.1 , Costa F.2,3 , Ko A.3,4 , Diggle P.J.1 Autónoma de México, Mexico City;
1 4
CHICAS, Faculty of Health and Medicine, Lancaster University, Sequencing Unit, National Institute of Genomic Medicine, México
Lancaster, UK; City;
2 5
Instituto de Saúde Coletiva, Universidade Federal da Bahia, Sal- School of Engineering and Sciences, Tecnológico de Monterrey,
vador, Brazil; Mexico City, Mexico
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