Nipah Virus Contamination of Hospital Surfaces during Outbreaks, Bangladesh, 2013-2014.

Nipah virus (NiV) has been transmitted from patient to caregivers in Bangladesh presumably through oral secretions. We aimed to detect whether NiV-infected patients contaminate hospital surfaces with the virus. During December 2013-April 2014, we collected 1 swab sample from 5 surfaces near NiV-infected patients and tested surface and oral swab samples by real-time reverse transcription PCR for NiV RNA. We identified 16 Nipah patients; 12 cases were laboratory-confirmed and 4 probable. Of the 12 laboratory-confirmed cases, 10 showed NiV RNA in oral swab specimens. We obtained surface swab samples for 6 Nipah patients; 5 had evidence of NiV RNA on >1 surface: 4 patients contaminated towels, 3 bed sheets, and 1 the bed rail. Patients with NiV RNA in oral swab samples were significantly more likely than other Nipah patients to die. To reduce the risk for fomite transmission of NiV, infection control should target hospital surfaces.

Care pathways of individuals with tuberculosis before and during the COVID-19 pandemic in Bandung, Indonesia.

The COVID-19 pandemic is thought to have undone years' worth of progress in the fight against tuberculosis (TB). For instance, in Indonesia, a high TB burden country, TB case notifications decreased by 14% and treatment coverage decreased by 47% during COVID-19. We sought to better understand the impact of COVID-19 on TB case detection using two cross-sectional surveys conducted before (2018) and after the onset of the pandemic (2021). These surveys allowed us to quantify the delays that individuals with TB who eventually received treatment at private providers faced while trying to access care for their illness, their journey to obtain a diagnosis, the encounters individuals had with healthcare providers before a TB diagnosis, and the factors associated with patient delay and the total number of provider encounters. We found some worsening of care seeking pathways on multiple dimensions. Median patient delay increased from 28 days (IQR: 10, 31) to 32 days (IQR: 14, 90) and the median number of encounters increased from 5 (IQR: 4, 8) to 7 (IQR: 5, 10), but doctor and treatment delays remained relatively unchanged. Employed individuals experienced shorter delays compared to unemployed individuals (adjusted medians: -20.13, CI -39.14, -1.12) while individuals whose initial consult was in the private hospitals experienced less encounters compared to those visiting public providers, private primary care providers, and informal providers (-4.29 encounters, CI -6.76, -1.81). Patients who visited the healthcare providers >6 times experienced longer total delay compared to those with less than 6 visits (adjusted medians: 59.40, 95% CI: 35.04, 83.77). Our findings suggest the need to ramp up awareness programs to reduce patient delay and strengthen private provide engagement in the country, particularly in the primary care sector.

Trends and correlates of low HIV knowledge among ever-married women of reproductive age: Evidence from cross-sectional Bangladesh Demographic and Health Survey 1996-2014.

BACKGROUND: The human immunodeficiency virus (HIV) burden has frequently been changing over time due to epidemiological and demographic transitions. To safeguard people, particularly women of reproductive age, who can be exposed to transmitting this burden to the next generation, knowledge regarding this life-threatening virus needs to be increased. This research intends to identify the trends and associated correlates of "low" HIV knowledge among ever-married women of reproductive age in Bangladesh from 1996 to 2014. METHODS: We analyzed data derived from six surveys of Bangladesh Demographic and Health Surveys conducted in 1996, 1999, 2004, 2007, 2011, and 2014. Analyses were primarily restricted to ever-married women aged 15-49 years who had ever heard of HIV. The correlates of "low" HIV knowledge were investigated using multiple binary logistic regression models. RESULTS: The study found that the proportion of women with "low" HIV knowledge decreased from 72% in 1996 to 58% in 2014. In adjusted models, age at first marriage, level of education, wealth quintile, and place of residence (except in the survey year 2011) were found to be potential correlates of "low" HIV knowledge in all survey years. In the pooled analysis, we found lower odds of "low" HIV knowledge in the survey years 1999 (Adjusted Odds Ratio: 0.67; 95% CI: 0.57, 0.78), 2004 (AOR: 0.60; 95% CI: 0.52, 0.70), 2007 (AOR: 0.51; 95% CI: 0.44, 0.60), 2011 (AOR: 0.36; 95% CI: 0.32, 0.42) and 2014 (AOR: 0.47; 95% CI: 0.41, 0.54) compared to the survey year 1996. CONCLUSION: The proportion of "low" HIV knowledge has declined over time, although the proportion of women with "low" HIV knowledge still remains high. The prevention of early marriage, the inclusion of HIV-related topics in the curricula, reduction of disparities between urban-rural and the poorest-richest groups may help to improve the level of HIV knowledge among ever-married Bangladeshi women.

Assessing sustained uptake of latrine and child feces management interventions: Extended follow-up of a cluster-randomized controlled trial in rural Bangladesh 1-3.5 years after intervention initiation.

BACKGROUND: Sanitation interventions typically result in modest increases in latrine access, and any gains in latrine access and use are often not sustained over time. Sanitation programs also rarely include child-focused interventions such as potties. We aimed to assess the sustained effect of a multi-component sanitation intervention on access to and use of latrines and child feces management tools in rural Bangladesh. METHODS: We conducted a longitudinal substudy nested within the WASH Benefits randomized controlled trial. The trial provided latrine upgrades, child potties and sani-scoops for feces removal, along with behavior change promotion to encourage use of the delivered hardware. Promotion visits to intervention recipients were frequent during the first 2 years after intervention initiation, decreased in frequency between years 2-3, and ceased after 3 years. We enrolled a random subset of 720 households from the sanitation and control arms of the trial in a substudy and visited them quarterly between 1 and 3.5 years after intervention initiation. At each visit, field staff recorded sanitation-related behaviors through spot-check observations and structured questionnaires. We assessed intervention effects on observed indicators of hygienic latrine access, potty use and sani-scoop use and investigated whether these effects were modified by duration of follow-up, ongoing behavior change promotion and household characteristics. RESULTS: The intervention increased hygienic latrine access from 37% among controls to 94% in the sanitation arm (p < 0.001). Access among intervention recipients remained high 3.5 years after intervention initiation, including periods with no active promotion. Gains in access were higher among households with less education, less wealth and larger number of residents. The intervention increased availability of child potties from 29% among controls to 98% in the sanitation arm (p < 0.001). However, fewer than 25% of intervention households reported exclusive child defecation in a potty or had observed indicators of potty and sani-scoop use, and gains in potty use declined over the follow-up period, even with ongoing promotion. CONCLUSION: Our findings from an intervention that provided free products and intensive initial behavior change promotion suggest a sustained increase in hygienic latrine access up to 3.5 years after intervention initiation but infrequent use of child feces management tools. Studies should investigate strategies to ensure sustained adoption of safe child feces management practices.

Exposure to Brucella spp. in Humans and Cows in a High Milk-Producing Area of Bangladesh.

Brucellosis is a zoonotic disease, caused by some species within the Brucella genus. The primary and secondary objectives of this cross-sectional study were to determine the seroprevalence of Brucella antibodies in humans and cows and identify risk factors for exposure to Brucella spp. among people in Shahjadpur sub-district, Bangladesh. Twenty-five villages were randomly selected from the 303 milk-producing villages in the sub-district. We randomly selected 5% of the total households from each village. At each household, we collected demographic information and history of potential exposure to Brucella spp. in humans. In addition, we collected serum from household participants and serum and milk from cattle and tested to detect antibodies to Brucella sp. Univariate analysis was performed to detect associations between seropositivity and demographics, risk factors, and behaviors in households. We enrolled 647 households, 1313 humans, and 698 cows. Brucella antibodies were detected in sera from 27 household participants (2.1%, 95% confidence interval [95%CI]: 1.2-2.9%). Eleven (1.6%, 95%CI 0.6-2.4%) cows had detectable Brucella antibodies in either milk or serum. About half (53%) of the 698 cows exhibited more than one reproductive problem within the past year; of these, seven (2%) had Brucella antibodies. Households with seropositive individuals more frequently reported owning cattle (78% vs. 32%, P < 0.001). Despite a low prevalence of Brucella seropositivity in the study, the public health importance of brucellosis cannot be ruled out. Further studies would help define Brucella prevalence and risk factors in this region and nationally.

Interpretation of molecular detection of avian influenza A virus in respiratory specimens collected from live bird market workers in Dhaka, Bangladesh: infection or contamination?

OBJECTIVES: Interpreting real-time reverse transcription-polymerase chain reaction (rRT-PCR) results for human avian influenza A virus (AIV) detection in contaminated settings like live bird markets (LBMs) without serology or viral culture poses a challenge. METHODS: During February-March 2012 and November 2012-February 2013, we screened workers at nine LBMs in Dhaka, Bangladesh, to confirm molecular detections of AIV RNA in respiratory specimens with serology. We tested nasopharyngeal (NP) and throat swabs from workers with influenza-like illness (ILI) and NP, throat, and arm swabs from asymptomatic workers for influenza virus by rRT-PCR and sera for seroconversion and antibodies against HPAI A(H5N1) and A(H9N2) viruses. RESULTS: Among 1273 ILI cases, 34 (2.6%) had A(H5), 56 (4%) had A(H9), and six (0.4%) had both A(H5) and A(H9) detected by rRT-PCR. Of 192 asymptomatic workers, A(H5) was detected in eight (4%) NP and 38 (20%) arm swabs. Of 28 ILI cases with A(H5) or A(H9) detected, none had evidence of seroconversion, but one (3.5%) and 12 (43%) were seropositive for A(H5) and A(H9), respectively. CONCLUSION: Detection of AIV RNA in respiratory specimens from symptomatic and asymptomatic LBM workers without evidence of seroconversion or virus isolation suggests environmental contamination, emphasizing caution in interpreting rRT-PCR results in high viral load settings.

Antibiotic use for acute respiratory infections among under-5 children in Bangladesh: a population-based survey.

INTRODUCTION: Despite acute respiratory infections (ARIs) being the single largest reason for antibiotic use in under-5 children in Bangladesh, the prevalence of antibiotic use in the community for an ARI episode and factors associated with antibiotic use in this age group are unknown. METHODS: We analysed nationally representative, population-based, household survey data from the Bangladesh Demographic and Health Survey 2014 to determine the prevalence of antibiotic use in the community for ARI in under-5 children. Using a causal graph and multivariable logistical regression, we then identified and determined the sociodemographic and antibiotic source factors significantly associated with the use of antibiotics for an episode of ARI. RESULTS: We analysed data for 2 144 children aged <5 years with symptoms of ARI from 17 300 households. In our sample, 829 children (39%) received antibiotics for their ARI episode (95% CI 35.4% to 42.0%). Under-5 children from rural households were 60% (adjusted OR (aOR): 1.6; 95% CI 1.2 to 2.1) more likely to receive antibiotics compared with those from urban households, largely driven by prescriptions from unqualified or traditional practitioners. Private health facilities were 50% (aOR: 0.5; 95% CI 0.3 to 0.7) less likely to be sources of antibiotics compared with public health facilities and non-governmental organisations. Age of children, sex of children or household wealth had no impact on use of antibiotics. CONCLUSION: In this first nationally representative analysis of antibiotic use in under-5 children in Bangladesh, we found almost 40% of children received antibiotics for an ARI episode. The significant prevalence of antibiotic exposure in under-5 children supports the need for coordinated policy interventions and implementation of clinical practice guidelines at point of care to minimise the adverse effects attributed to antibiotic overuse.

Knowledge and attitudes associated with menopause among women aged 45 to 60 years: a pilot study among rural and urban women in Bangladesh.

OBJECTIVE: To assess knowledge and attitudes associated with the menopause transition among women in Bangladesh. METHODS: A cross-sectional survey was conducted among women (age range 45-60 y), 160 participants were selected from both urban and rural settings using a systematic sampling procedure. We used face-to-face interview techniques employing a semistructured questionnaire. Bivariate and multivariate regression analyses were done to assess the associated factors. RESULTS: Around one-fourth (23%) of the participants did not have a basic understanding about symptoms of menopause. Knowledge about menopause increased proportionately with higher education levels (primary education, risk ratio [RR] = 3.91, 95% confidence interval [CI] = 0.66-22.92; secondary education, RR = 6.10, 95% CI = 1.26-29.41; higher education, RR = 6.74, 95% CI = 1.33-34) and was more common among urban than rural women (P = 0.001). In addition, women who were service holders had greater knowledge about menopause compared with women who worked in the home (RR = 8.67, 95% CI = 1.94-38.58). Most of the women (96%) suffered from different kinds of depression during the menopause transition. Key barriers to gaining knowledge about menopause included access to information (63%), social stigma (57%), and shame (52%). CONCLUSIONS: Menopause is a neglected issue in Bangladesh. Accurate and appropriate information regarding premenopause and menopause can help women cope with this life transition. Social and familial support may also play a role in minimizing isolation and depression. Public health messaging to increase awareness and knowledge about menopause should be undertaken to overcome the stigma and shame associated with menopause in Bangladesh. : Video Summary:http://links.lww.com/MENO/A556.

Video Summary:http://links.lww.com/MENO/A556.

Epidemiology and genotypes of group A rotaviruses in cattle and goats of Bangladesh, 2009-2010.

Group A rotavirus (RVA) is recognized as a major cause of severe gastroenteritis in newborn calves and goat kids. We estimated the proportion of ruminants infected with rotavirus and identified the circulating genotypes in cattle and goats in Bangladesh. Between May 2009 and August 2010, fecal samples were collected from 520 cattle and goats presenting with diarrhea at three government veterinary hospitals in three districts of Bangladesh. All samples were screened for RVA RNA using real-time, one-step, reverse transcription polymerase chain reaction (qRT-PCR). Of the 520 animals tested, 11.7% (61) were positive for RVA RNA, with 6.2% (15/241) and 16.5% (46/279) positivity in cattle and goats, respectively. RVA positive samples were further characterized by nucleotide sequence analysis of two structural protein gene fragments, VP7 (G genotype), and VP4 (P genotype). Among 17 successfully sequenced strains, G8 (17.9%) was the most prevalent G-genotype followed by G10 (8%) and G6 (1.6%). P[1] (11.3%) was the most frequently detected P-genotype followed by P[11] (3.2%) and P[15] (1.6%). The most common VP7/VP4 combinations for cattle were G10P[11], G10P[15], and G6P[11], and for goat, G8P[1], and G10P[1]. Phylogenetic analysis of the RVA strains showed clustering with bovine and caprine strains from neighboring India. The study adds to our understanding of the genetic diversity of bovine and caprine rotavirus strains in Bangladesh. Our findings highlight the importance of rotavirus surveillance in cattle and goat populations, which may serve as a potential source for genetic reassortment and zoonotic transmission.

Child defecation and feces management practices in rural Bangladesh: Associations with fecal contamination, observed hand cleanliness and child diarrhea.

Child open defecation is common in low-income countries and can lead to fecal exposure in the domestic environment. We assessed associations between child feces management practices vs. measures of contamination and child diarrhea among households with children <5 years in rural Bangladesh. We visited 360 households quarterly and recorded caregiver-reported diarrhea prevalence, and defecation and feces disposal practices for children <5 years. We examined caregiver and child hands for visible dirt and enumerated E. coli in child and caregiver hand rinse and stored drinking water samples. Safe child defecation (in latrine/potty) and safe feces disposal (in latrine) was reported by 21% and 23% of households, respectively. Controlling for potential confounders, households reporting unsafe child defecation had higher E. coli prevalence on child hands (prevalence ratio [PR] = 1.12, 1.04-1.20) and in stored water (PR = 1.12,1.03-1.21). Similarly, households reporting unsafe feces disposal had higher E. coli prevalence on child hands (PR = 1.11, 1.02-1.21) and in stored water (PR = 1.10, 1.03-1.18). Effects on E. coli levels were similar. Children in households with unsafe defecation and feces disposal had higher diarrhea prevalence but the associations were not statistically significant. Our findings suggest that unsafe child feces management may present a source of fecal exposure for young children.

Trends and clinico-epidemiological features of human rabies cases in Bangladesh 2006-2018.

Vaccinating dogs against rabies is an effective means of reducing human rabies. We subjected 1327 clinically diagnosed human rabies death and mass dog vaccination (MDV) data during 2006-2018 to quantify the impacts of MDV on human rabies incidence in Bangladesh and a subset of rabies death data (422) for clinico-epidemiological analysis. A positive and increasing trend of MDV (p = 0.01 and tau = 0.71) and a negative and declining trend (p < 0.001 and tau = -0.88) of human rabies cases (Correlation coefficient: -0.82) have been observed. Among 422 deaths, the majority (78%) of the victims sought treatment from traditional healers, and 12% received post-exposure prophylaxis (PEP). The mean incubation period of rabies in cases with exposure sites on the head & neck (35 days) was shorter than the upper limb (mean = 64 days, p = 0.02) and lower limb (mean = 89 days, p < 0.01). MDV has been found to be effective for reducing human rabies cases in Bangladesh. Creating awareness among the animal bite victims to stop reliance on traditional healers rather seeking PEP, addressing the role of traditional healers through awareness education programme with respect to the treatment of dog bites, ensuring availability of PEP, and continuing to scale up MDV may help to prevent human rabies deaths.

Role of Qualified Physicians as Antenatal Care Providers in Reducing Birth Complications in Home-delivered Rural Women in Bangladesh.

Introduction Bangladesh has made significant strides in maternal and neonatal death by ensuring qualified antenatal care (ANC) visits during the pregnancy period of women. To ensure this qualified ANC, the government of Bangladesh has increased the number of qualified physicians and skilled birth attendants at health facilities and encouraged pregnant women to take this eligible ANC during pregnancy. Despite this progress, the majority of deliveries among rural women still occur at home, assisted by traditional birth attendants. These traditional birth attendants at home or even skilled birth attendants at the health facility or home are not always cable of helping women to overcome severe delivery complications. Proper birth preparation before pregnancy through qualified ANC might be a solution here. Taking advice for appropriate birth preparation from a qualified physician (medical doctor) would ensure qualified ANC. In this study, we examined how ANC from a qualified physician, as compared to other trained providers, influences rural women delivering at home to prepare for birth and reduces severe delivery complications. Methods The data of 1554 rural women who delivered at home were extracted from the 2014 Bangladesh Demographic and Health Survey data. A mixed-effects logistic regression model was carried out for the binary delivery complications data, to assess the influence of qualified physicians as ANC providers on delivery complications by adjusting the effect of other socio-demographic covariates and clustering. Results Of the women from rural areas who delivered at home, 42% reported delivery complications. Those who received ANC from a qualified physician were 32% less likely (OR 0.68; 95% CI 0.50, 0.91) to report facing delivery complications as compared to those who had received ANC from other trained or unqualified providers adjusted by socio-demographic determinants in Bangladesh. Conclusions Developing a sustained and effective strategy could be a precedent for promoting ANC from qualified physicians for rural women delivering at home, to decrease delivery complications as well as creating healthy environments for safe deliveries.

Host Selection of Field-Collected Anopheles jeyporiensis and Anopheles nivipes in Bangladesh.

Anopheles jeyporiensis and Anopheles nivipes appear to play an important role in contemporary malaria transmission in Bangladesh. However, very little is known about the natural host selection of these vectors. Therefore, host selection of these two species was investigated in Bandarban, the most malarious region of Bangladesh. A total of 480 engorged mosquitoes were analyzed. The human blood index (HBI) of An. jeyporiensis varied from 4.17% in outdoor to 19.17% in indoor collections. Similarly, HBI of An. nivipes ranged between 0.83% and 22.50% from outdoor to indoor. For both species, cow blood indices were significantly higher than HBI in both indoor and outdoor collections. These data demonstrate the opportunistic and zoophilic nature of An. jeyporiensis and An. nivipes, which suggests that approaches such as zooprophylasis may prove beneficial as a control strategy.

Abundance and Dynamics of Anopheles (Diptera: Culicidae) Larvae in a Malaria Endemic Area of Bangladesh.

Malaria is a major health burden in the border-belt areas of Bangladesh. There are recent data from adult mosquito collections that a number of vectors are involved in the transmission cycle. However, little information regarding the larval habitats of Anopheles mosquitoes are available in Bangladesh. To start filling this gap, a cross-sectional larval survey was conducted in Bandarban, Bangladesh from October 2011 to September 2012. Descriptive analysis, Poisson regression, spearman correlations and zero-inflated Poisson regression were used to calculate the degree of association between the abundance of larval Anopheles species and environmental factors. From the 300 larval habitats sampled, 5,568 Anopheles larvae were collected and of these, 2,263 (40.6%) were identified to species. Collections represented 16 Anopheles species with Anopheles vagus (26.4%, n = 598) as the dominant species. A total of 16 Anopheles larval habitat types were identified. Larval abundance was significantly different (P < 0.05) among habitats with pond (40%, n = 914) and rice field (34%, n = 779) implicated to be the most utilized. Larval abundance varied significantly (P < 0.05) with habitat characteristics. Most of the larvae were collected from sites with a range of pH from 7.0 to 8.0. Data obtained from this study revealed both natural and human-created larval habitats were favorable for anopheline larval survival and development. Such information elucidates plausible drivers of high anopheline diversity, high vector abundance, changes in relative species abundance from historic data, and sustained transmission of malaria in endemic areas of Bangladesh.

Prevalence of Type 2 Diabetes Mellitus Among Urban Bihari Communities in Dhaka, Bangladesh: A Cross-sectional Study in a Minor Ethnic Group.

Introduction The prevalence, disease progression, and treatment outcomes for patients with type 2 diabetes vary significantly between ethnic groups. The Bihari community constitutes one of the most vulnerable populations in Bangladesh on the basis of access to health services and other fundamental rights. Our study aimed at finding out the prevalence and risk factors of type 2 diabetes among the Bihari adults in Dhaka city. Methods This cross-sectional community-based study was carried out among stranded Pakistanis (known as Bihari) living in camps in the Mirpur area from July 2014 to June 2015. Laboratory-based oral glucose tolerance test (OGTT) was the basis for the diagnosis of type 2 diabetes mellitus (DM). Anthropometric measurements, blood pressure, biochemical tests, family history, and socioeconomic information were obtained to determine the risk factors. Results The prevalence of diabetes mellitus (DM), impaired glucose tolerance (IGT), and impaired fasting glucose (IFG) were estimated at 10.11%, 8.74%, and 4.55%, respectively. Increased diastolic blood pressure, serum triglyceride, and cholesterol level were observed to be significantly (p < 0.05) associated with diabetes. Also, the presence of diabetes, high blood pressure, and obesity among relatives significantly increased the probability of diabetes. Conclusions To the best of our knowledge, this is the first study on diabetes prevalence among the Bihari community in Bangladesh. The prevalence of type 2 diabetes mellitus was found to be higher among the Bihari community compared to the general population in Bangladesh. Health planners and policymakers should realize the alarming situation and identified risk factors and consider the minor ethnic groups during decision-making regarding prevention and control of diabetes and other noncommunicable diseases.

Risk factors for the presence of dengue vector mosquitoes, and determinants of their prevalence and larval site selection in Dhaka, Bangladesh.

Dengue viruses are responsible for over 100 million infections a year worldwide and are a public health concern in Bangladesh. Although risk of transmission is high, data on vector population characteristics are scanty in Bangladesh; therefore, a comprehensive prediction of the patterns of local virus transmission is not possible. Recognizing these gaps, multi-year entomological surveys were carried out in Dhaka, where the disease is most frequently reported. The specific objectives of the present study are threefold: i) to determine the risk factors for the presence of Aedes mosquitoes; ii) to identify the types of most productive and key containers; and iii) to estimate the effects of climatic factors on Aedes abundance in the city of Dhaka, Bangladesh. Entomological surveys were conducted in 12 out of 90 wards in Dhaka. These wards were selected using a probability proportional sampling procedure during the monsoon seasons in 2011, 2012 and 2013 and in the dry season in 2012. All containers inside and around sampled households were inspected for mosquito larvae and pupae, and containers were classified according to their relative size, use pattern, and materials of construction. During the study period (2011-2013), 12,680 larvae and pupae were collected. About 82% of the identified immature mosquitoes were Aedes aegypti, while the remainder were Ae. albopictus and other mosquito species. The largest number of immature mosquitoes was collected from tires and refrigerator trays during 2011 and 2012 monsoon seasons. Conversely, plastic drums were the most productive during the 2012 dry and 2013 monsoon season. Vehicle parts and discarded construction materials were the most efficient producers of Aedes mosquitoes in all surveys. The presence of Aedes mosquitoes was significantly (p < 0.05) higher in low socio-economic zones of Dhaka. Container location, presence of vegetation, and availability of shade for containers were also significantly associated with finding immature Aedes mosquitoes, based on multivariable analysis after confounder adjustment. Rainfall, temperature, and relative humidity also significantly affected the mean abundance of mosquitoes. Proper use, disposal, and recycling of the containers that effectively produce large numbers of Aedes vector mosquitoes may decrease the risk of arboviral transmission.

Role of underappreciated vectors in malaria transmission in an endemic region of Bangladesh-India border.

BACKGROUND: Despite the efforts of the National Malaria Control Programme, malaria remains as an important public health problem in Bangladesh, particularly in the south-eastern region bordering India. Successful malaria control strategies rely on a detailed understanding of the underlying causes of malaria transmission. Here, an entomological survey was conducted in a malaria endemic area of Bangladesh bordering India to investigate the Anopheles mosquito community and assess their Plasmodium infection status. METHODS: Monthly entomological collections were undertaken from October 2010 to September 2011 in five villages in the Matiranga sub-district, Khagrachari district in Bangladesh, bordering the Indian State of Tripura. CDC miniature light traps were placed inside houses to collect adult Anopheles mosquitoes. Following morphological and molecular identification of the female Anopheles mosquitoes collected, they were screened for circumsporozoite proteins (CSP) of Plasmodium falciparum (Pf), Plasmodium vivax-210 (Pv-210) and Plasmodium vivax-247 (Pv-247), by ELISA to determine natural infection rates. Variation in Anopheles species composition, relative abundance and Plasmodium infection rates were analysed between sampled villages. RESULTS: A total of 2,027 female Anopheles were collected, belonging to 20 species. Anopheles nivipes was the most abundant species in our test villages during the peak malaria transmission season, and was observed sympatrically with An. philippinensis in the studied area. However, in the dry off-peak season, An. jeyporiensis was the most abundant species. Shannon's diversity index was highest in October (2.12) and evenness was highest in May (0.91). The CSP ELISA positive rate overall was 0.44%. Anopheles karwari (n=2), An. barbirostris s.l. (n=1) and An. vagus (n=1) were recorded positive for Pf. Anopheles kochi (n=1) was positive for Pv-210 while An. umbrosus (n=1), An. nivipes (n=1) and An. kochi (n=1) were positive for Pv-247. A mixed infection of Pf and Pv-247 was detected in An. barbirostris s.l.. CONCLUSION: High diversity of Anopheles species was observed in areas close to the international border where species that were underestimated for malaria transmission significantly outnumbered principal vector species and these may play a significantly heightened role in malaria transmission.