Entomological aspects and the role of human behaviour in malaria transmission in a highland region of the Republic of Yemen

© 2016 Al-Eryani et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article

Prevalence and Risk Factors for Trichomonas vaginalis Infection among Pregnant Women Seeking Primary Health Care in Sana'a City, Yemen

Objective: To determine the prevalence and risk factors for Trichomonas vaginalis infection among pregnant women seeking health care in Sana’a city. Methods: This cross-sectional study was conducted among pregnant women seeking health care in private clinics and governmental primary health care centers in Sana’a during the period from October 2014 to June 2015. Data on sociodemographic and clinical characteristics as well as possible risk factors of T. vaginalis infection were collected from 287 pregnant women using a pre-designed questionnaire by trained researchers. Vaginal discharges were then collected and examined microscopically for motile T. vaginalis trophozoites. Results: The overall prevalence of T. vaginalis infection was 11.1%, with a higher infection rate among pregnant women aged 26-40 years old, housewives and rural residents. Age, literacy status and the age at first sexual intercourse were significantly associated with T. vaginalis infection among pregnant women. Presence of vaginal discharge (OR = 8.33; 95% CI: 2.47–28.03, P <0.001), itching (OR = 2.57; 95% CI: 1.02–6.48, P = 0.027) and presence of unpleasant odor (OR = 4.37; 95% CI: 1.63–11.70, P = 0.001) were the clinical manifestations significantly associated with T. vaginalis among pregnant women. Conclusions: T. vaginalis is prevalent among pregnant women seeking health care in Sana’a, particularly housewives, illiterate women and those coming from rural areas. Presence of vaginal discharge with unpleasant odor and itching are associated with a higher risk of infection among symptomatic women. Further large-scale studies are required to determine the prevalence and risk factors among women of the reproductive age in Yemen

Access to and use of long-lasting insecticidal nets and factors associated with non-use among communities in malaria-endemic areas of Al Hudaydah governorate in the Tihama region, west of Yemen

Abstract Background Universal coverage of the targeted malaria-endemic areas with long-lasting insecticidal nets (LLINs) is implemented as one of the key interventions for malaria control and elimination in Yemen. In 2013, through a mass campaign, LLINs were distributed to the targeted communities in Al Hudaydah governorate. This study aimed to assess the ownership of, access to, and use of LLINs. It also aimed to identify factors associated with not using LLINs in malaria-endemic areas of Al Hudaydah in the Tihama region, west of Yemen. Methods A cross-sectional survey was conducted in four districts (Ad Durayhimi, Al Marawi’ah, Al Mansuriyah and Bayt Al Faqiah) in Al Hudaydah during February 2016. A total of 701 households were included in this study. Data on socio-demographic characteristics and availability of LLINs were collected by interview and observation. Four indicators for malaria prevention using LLINs; proportion of households with at least one LLIN, proportion of households with at least one LLIN for every two people, proportion of population with access to LLINs in the surveyed households and proportion of population who slept under LLINs the previous night of the survey were calculated as indicated by Roll Back Malaria Monitoring and Evaluation Reference Group. Use to access ratio was assessed. Factors associated with not using LLINs among people with access were also investigated. Results Of 701 households with 4900 de facto population, ownership of at least one LLIN was 90.6%, while 24.1% owned at least one for every two people during the survey in 2016. The overall proportion of people with access to LLINs was 51.5% (95% CI 50.1–52.9). Only 19.0% (95% CI 17.9–20.1) slept under LLINs the night before the survey and the overall use to access ratio was 0.37. The proportions of children under 5 years of age with access to and use of LLINs were 13.7 and 42.5%, respectively. On the other hand, the proportions of pregnant women with access to and use of LLINs were 16.4 and 20.0%, respectively. Multivariable analysis identified that people living in Al Mansuriyah district [adjusted odds ratio (AOR) = 3.29, 95% confidence interval (CI)  1.35–8.01; P = 0.009)], having three or more damaged LLINs in the house (AOR = 2.76, 95% CI 1.79–4.25; P < 0.001), aged between 16 and 45 years old (AOR = 2.17, 95% CI 1.26–3.75; P = 0.005) or older (AOR = 2.17, 95% CI 1.09–4.29; P = 0.026) and living in huts (AOR = 1.59, 95% CI 1.09–2.32; P = 0.015) were significantly less likely to use LLINs. Conclusions This study shows a low LLIN access rate among local communities targeted for universal LLIN coverage in Al Hudaydah, a malaria-endemic area of high transmission. This finding necessitates additional distribution channels following mass campaigns to maintain the universal coverage. Reduced use of LLINs among people with access in these communities together with the identified risks of non-use highlight the importance of conducting behaviour change communication campaigns to enhance using LLINs in areas with universal coverage

First Molecular Characterization of Leishmania Species Causing Visceral Leishmaniasis among Children in Yemen.

Visceral leishmaniasis (VL) is a debilitating, often fatal disease caused by Leishmania donovani complex; however, it is a neglected tropical disease. L. donovani complex comprises two closely related species, L. donovani that is mostly anthroponotic and L. infantum that is zoonotic. Differentiation between these two species is critical due to the differences in their epidemiology and pathology. However, they cannot be differentiated morphologically, and their speciation using isoenzyme-based methods poses a difficult task and may be unreliable. Molecular characterization is now the most reliable method to differentiate between them and to determine their phylogenetic relationships. The present study aims to characterize Leishmania species isolated from bone marrows of Yemeni pediatric patients using sequence analysis of the ribosomal internal transcribed spacer-1 (ITS1) gene. Out of 41 isolates from Giemsa-stained bone marrow smears, 25 isolates were successfully amplified by nested polymerase chain reaction and sequenced in both directions. Phylogenetic analysis using neighbor joining method placed all study isolates in one cluster with L. donovani complex (99% bootstrap). The analysis of ITS1 for microsatellite repeat numbers identified L. infantum in 11 isolates and L. donovani in 14 isolates. These data suggest the possibility of both anthroponotic and zoonotic transmission of VL-causing Leishmania species in Yemen. Exploring the possible animal reservoir hosts is therefore needed for effective control to be achieved

Multisectoral Approach to Address Chikungunya Outbreaks Driven by Human Mobility: A Systematic Review and Meta-Analysis

The role of human mobility in the epidemiology of emerging Aedes-transmitted viral diseases is recognized but not fully understood. The objective of this systematic review and meta-analysis was to examine how human mobility patterns are driving chikungunya outbreaks. Literature was systematically reviewed for studies on chikungunya prevalence in countries/territories with high-level evidence of human mobility-driven outbreaks, based on: (1) emergence of chikungunya outbreaks with epidemic chikungunya virus genotypes among displaced/migrant populations and their hosting communities; and (2) identification of imported index case(s) with epidemic genotypes phylogenetically related to the genotypes circulating during emerging or subsequent outbreaks. The meta-analysis of extracted prevalence data revealed that a large proportion of the population in countries/territories afflicted by outbreaks is still at risk of infection during future outbreaks. On the other hand, approximately one-half of suspected chikungunya cases could be infected with other co-circulating acute febrile illnesses. We discussed in this paper how human mobility-driven chikungunya outbreaks can be addressed, and how the involvement of several sectors in addition to the health sector in multisectoral approaches (MSAs) is important for prevention and control of chikungunya and other Aedes-transmitted arboviral outbreaks

Impact of population displacement and forced movements on the transmission and outbreaks of Aedes-borne viral diseases: Dengue as a model

[Display omitted] •Population displacement and forced human movements impact the spatiotemporal epidemiology of dengue.•Risk mapping of transmission “hotspots” in displacement settings is needed for better multi-sectoral prevention and control.•Phylogenetic analysis of virus isolates in outbreaks is needed to understand the impact of dengue in displacement settings.•The changing landscape of how displaced populations are infected with dengue is challenging to public health policymakers. Population displacement and other forced movement patterns following natural disasters, armed conflicts or due to socioeconomic reasons contribute to the global emergence of Aedes-borne viral disease epidemics. In particular, dengue epidemiology is critically affected by situations of displacement and forced movement patterns, particularly within and across borders. In this respect, waves of human movements have been a major driver for the changing epidemiology and outbreaks of the disease on local, regional and global scales. Both emerging dengue autochthonous transmission and outbreaks in countries known to be non-endemic and co-circulation and hyperendemicity with multiple dengue virus serotypes have led to the emergence of severe disease forms such as dengue hemorrhagic fever and dengue shock syndrome. This paper reviews the emergence of dengue outbreaks driven by population displacement and forced movements following natural disasters and conflicts within the context of regional and sub-regional groupings

Microsatellite repeat numbers of ITS1 gene found for <i>L</i>. <i>donovani</i> complex isolates from Yemeni children infected with VL compared to reference strains.^a

<p>Microsatellite repeat numbers of ITS1 gene found for <i>L</i>. <i>donovani</i> complex isolates from Yemeni children infected with VL compared to reference strains.<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0151265#t001fn001" target="_blank">^a</a></p

<i>Onchocerca volvulus</i> infection in Tihama region - west of Yemen: Continuing transmission in ivermectin-targeted endemic foci and unveiled endemicity in districts with previously unknown status

<div><p>Background</p><p>Onchocerciasis in Yemen is one of the most neglected diseases, where baseline estimates of onchocerciasis and monitoring of the impact of ivermectin regularly administered to the affected individuals on its transmission are lacking. Therefore, this study aimed to determine the anti-<i>Ov</i>16 IgG4 seroprevalence among local communities of Hodeidah and Al-Mahwit governorates of Tihama region. The factors possibly associated with previous exposure to infection were also studied.</p><p>Methodology/Principal findings</p><p>This cross-sectional study was conducted in two ivermectin-targeted districts endemic for onchocerciasis in Hodeidah and Al-Mahwit and two untargeted districts with unknown previous endemicity in Hodeidah between February and July 2017. For 508 residents sampled by a multi-stage random approach, data were collected and blood specimens were screened for anti-<i>Ov</i>16 IgG4 using the SD BIOLINE Onchocerciasis IgG4 rapid tests. The study revealed an overall anti-<i>Ov</i>16 IgG4 rate of 18.5% (94/508) in all surveyed districts, with 10.2% (12/118) of children aged ≤10 years being seropositive. Moreover, rates of 8.0% (4/50) and 6.1% (4/66) were found in districts not officially listed as endemic for the disease. Multivariable analysis confirmed the age of more than ten years and residing within a large family as the independent predictors of exposure to infection.</p><p>Conclusions/Significance</p><p>Onchocerciasis transmission is still ongoing as supported by the higher anti-<i>Ov</i>16 IgG4 seroprevalence rate among children aged ≤10 years compared to that (<0.1%) previously set by the World Health Organization as a serologic criterion for transmission interruption. Further large-scale studies combining serologic and entomologic criteria are recommended for the mapping of <i>O</i>. <i>volvulus</i> in human and blackfly populations in endemic foci and their neighboring areas of uncertain endemicity. In addition, ivermectin distribution, coverage and impact on disease transmission need to be continually assessed.</p></div

Phylogenetic study of <i>L</i>. <i>donovani</i> complex causing VL among Yemeni children.

<p>Unrooted NJ phylogenetic tree showing the relationships of 25 ITS1 sequences of <i>Leishmania</i> species isolates from Yemeni children with VL and sequences representing <i>L</i>. <i>infantum</i>, <i>L</i>. <i>donovani</i>, <i>L</i>. <i>major</i>, <i>L</i>. <i>tropica</i> and <i>L</i>. <i>aethiopica</i>. Bold-type represents reference sequences from GenBank. Abbreviations of countries of origib: FR, France; ES, Spain; PT, Portugal; CN, China; MT, Malta; SD, Sudan; ET, Ethiopia; KE, Kenya; IN, India; TN, Tunisia, YE, Yemen.</p