Immunochromatographic Card Research Articles

Prevalence and risk factors associated with lymphatic filariasis in American Samoa after mass drug administration

BackgroundIn 2000, American Samoa had 16.5% prevalence of lymphatic filariasis (LF) antigenemia. Annual mass drug administration (MDA) was conducted using single-dose albendazole plus diethylcarbamazine from 2000 to 2006. This study presents the results of a 2007 population-based PacELF C-survey in all ages and compares the adult filarial antigenemia results of this survey to those of a subsequent 2010 survey in adults with the aim of improving understanding of LF transmission after MDA.ResultsThe 2007 C-survey used simple random sampling of households from a geolocated list. In 2007, the overall LF antigen prevalence by immunochromatographic card test (ICT) for all ages was 2.29% (95% CI 1.66–3.07). Microfilaremia prevalence was 0.27% (95% CI 0.09–0.62). Increasing age (OR 1.04 per year, 95% CI 1.02–1.05) was significantly associated with ICT positivity on multivariate analysis, while having ever taking MDA was protective (OR 0.39, 95% CI 0.16–0.96). The 2010 survey used a similar spatial sampling design.The overall adult filarial antigenemia prevalence remained relatively stable between the surveys at 3.32% (95% CI 2.44–4.51) by ICT in 2007 and 3.23 (95% CI 2.21–4.69) by Og4C3 antigen in 2010. However, there were changes in village-level prevalence. Eight village/village groupings had antigen-positive individuals identified in 2007 but not in 2010, while three villages/village groupings that had no antigen-positive individuals identified in 2007 had positive individuals identified in 2010.ConclusionsAfter 7 years of MDA, with four rounds achieving effective coverage, a representative household survey in 2007 showed a decline in prevalence from 16.5 to 2.3% in all ages. However, lack of further decline in adult prevalence by 2010 and fluctuation at the village level showed that overall antigenemia prevalence at a broader scale may not provide an accurate reflection of ongoing transmission at the village level.

Lymphatic Filariasis in Mainland Southeast Asia: A Systematic Review and Meta-Analysis of Prevalence and Disease Burden.

Accurate prevalence data are essential for the elimination of lymphatic filariasis (LF) as a public health problem. Despite it bearing one of the highest burdens of disease globally, there remains limited reliable information on the current epidemiology of filariasis in mainland Southeast Asia. We conducted a systematic review and meta-analysis of available literature to assess the recent and current prevalence of infection and morbidity in the region. Fifty-seven journal articles and reports containing original prevalence data were identified, including over 512,010 participants. Data were summarised using percentage prevalence estimates and a subset combined using a random effects meta-analysis by country and year. Pooled estimates for microfilaraemia, immunochromatographic card positivity and combined morbidity were 2.64%, 4.48% and 1.34% respectively. Taking into account pooled country estimates, grey literature and the quality of available data, we conclude that Lao People's Democratic Republic (PDR), Myanmar and Northeast India demonstrate ongoing evidence of LF transmission that will require multiple further rounds of mass drug administration. Bangladesh, Malaysia, Thailand and Vietnam appear close to having eliminated LF, whilst Cambodia has already achieved elimination status. We estimate that the burden of morbidity is likely high in Thailand; moderate in Cambodia, Myanmar, and Northeast India; and low in Bangladesh. There was insufficient evidence to accurately estimate the disease burden in Lao PDR, Malaysia or Vietnam. The results of this study indicate that whilst considerable progress toward LF elimination has been made, there remains a significant filariasis burden in the region. The results of this study will assist policy makers to advocate and budget for future control programs.

Risk Factors for Podoconiosis: Kamwenge District, Western Uganda, September 2015.

AbstractPodoconiosis, a noninfectious elephantiasis, is a disabling neglected tropical disease. In August 2015, an elephantiasis case-cluster was reported in Kamwenge District, western Uganda. We investigated to identify the disease's nature and risk factors. We defined a suspected podoconiosis case as onset in a Kamwenge resident of bilateral asymmetrical lower limb swelling lasting ≥ 1 month, plus ≥ 1 of the following associated symptoms: skin itching, burning sensation, plantar edema, lymph ooze, prominent skin markings, rigid toes, or mossy papillomata. A probable case was a suspected case with negative microfilaria antigen immunochromatographic card test (ruling out filarial elephantiasis). We conducted active case-finding. In a case-control investigation, we tested the hypothesis that the disease was caused by prolonged foot skin exposure to irritant soils, using 40 probable case-persons and 80 asymptomatic village control-persons, individually matched by age and sex. We collected soil samples to characterize irritants. We identified 52 suspected (including 40 probable) cases with onset from 1980 to 2015. Prevalence rates increased with age; annual incidence (by reported onset of disease) was stable over time at 2.9/100,000. We found that 93% (37/40) of cases and 68% (54/80) of controls never wore shoes at work (Mantel-Haenszel odds ratio [ORMH] = 7.7; 95% [confidence interval] CI = 2.0-30); 80% (32/40) of cases and 49% (39/80) of controls never wore shoes at home (ORMH = 5.2; 95% CI = 1.8-15); and 70% (27/39) of cases and 44% (35/79) of controls washed feet at day end (versus immediately after work) (OR = 11; 95% CI = 2.1-56). Soil samples were characterized as rich black-red volcanic clays. In conclusion, this reported elephantiasis is podoconiosis associated with prolonged foot exposure to volcanic soil. We recommended foot hygiene and universal use of protective shoes.

Lymphatic filariasis elimination efforts in Rufiji, southeastern Tanzania: decline in circulating filarial antigen prevalence in young school children after twelve rounds of mass drug administration and utilization of long-lasting insecticide-treated nets

Lymphatic filariasis (LF) is a parasitic infection transmitted by mosquito vectors, and in Sub-Saharan Africa it is caused by the nematode Wuchereria bancrofti. The disease has been targeted for global elimination with the annual mass drug administration (MDA) strategy. Vector control is known to play an important complementary role to MDA in reducing the transmission of LF. The effects of an MDA and insecticide-treated net intervention implemented in an endemic area of southeastern Tanzania are reported here. A cross-sectional study assessing W. bancrofti circulating filarial antigen (CFA) was conducted in five primary schools in five different villages. Standard one pupils aged 6-9 years were screened for CFA using immunochromatographic test cards (ICT), with a total of 413 screened in 2012 and 659 in 2015. Just after CFA testing, the children were interviewed on their participation in the MDA campaign. Moreover, 246 heads of households in 2012 and 868 in 2015 were interviewed on their participation in MDA and utilization of long-lasting insecticide-treated nets (LLINs). The prevalence of CFA for the 413 children tested in 2012 was 14.3%, while it was 0.0% for the 659 children tested in 2015. The Tanzanian National Lymphatic Filariasis Elimination Programme reported annual treatment coverage for Rufiji District ranging from 54.3% to 94.0% during the years 2002-2014. The surveyed treatment was 51.6% in 2011 and 57.4% in 2014. With regard to LLINs, possession and utilization increased from 63.4% and 59.2%, respectively, in 2012, to 92.5% and 75.4%, respectively, in 2015. The findings suggest that 12 rounds of MDA complemented with vector control through the use of insecticide-treated nets resulted in a marked reduction in W. bancrofti CFA in young school children.

Clinico-epidemiological profile of dengue cases in a Medical College Hospital, Bengaluru, Karnataka, India

Background: Medical college hospital being a tertiary care center receives a significant number of dengue cases from within and outside the catchment area and provides a good opportunity to study the clinical and epidemiological features of dengue infection, its prognosis and outcome so as to institute prompt preventive and control measures. The objective was to describe the clinico-epidemiological features of dengue cases admitted to pediatric ward at a Medical College Hospital, Bengaluru, Karnataka, India.Methods: Cross-sectional study of 140 cases positive for NS1Ag, IgM and/or IgG by dengue rapid immuno-chromatographic card test, admitted in pediatric ward during June to August 2013 at Rajarajeswari Medical College and Hospital.Results: Majority of the patients were from rural area. Fever was present in all 140 cases. Vomiting followed by headache were the common presenting symptoms. Of the 140, 50% cases were classified as dengue fever without warning signs, 46.4% as dengue fever with warning signs and 3.6% as severe dengue. Thrombocytopenia was present in 77.1%, leucopenia in 47.9%, and raised haematocrit in 52.1% of cases. Mortality rate was 0.71%.Conclusions: Children above 5 years of age were most commonly affected age group. About 5 (3.6%) of the patients belonged to severe dengue category according to revised WHO Dengue Case Classification.

Molecular xenomonitoring (MX) and transmission assessment survey (TAS) of lymphatic filariasis elimination in two villages, Menoufyia Governorate, Egypt.

Lymphatic filariasis (LF) is focally endemic in Egypt where the female mosquito, Culex pipiens, is responsible for its transmission. The aim of the study was to investigate the impact of implementation of the 13th round of MDA in two Egyptian villages in the Menoufyia Governorate area after failing the transmission assessment survey (TAS) in 2005 using two methods, and to decide whether it is safe to stop MDA in these, as well as in similar implementation units (IUs). To achieve this aim, both the immunochromatographic card test (ICT) and molecular xenomonitoring (MX) techniques were employed. A cross-sectional study was carried out in the villages in 2014 with two sections: Section (1): a school-based survey where all the primary school entrants (6-7) years of age were tested by ICT. Section (2): a mosquito-based survey where a total of 152 mosquito pools collected from Samalay and 167 from Kafr El-Tarainah were tested for the presence of the gDNA of Wuchereria bancrofti microfilaria by real-time PCR assays. The results revealed that all primary school children in both villages were 100% negative for antigenemia. Also, all mosquito pools were 100% negative for the microfilarial gDNA.

INTERRUPTED BANCROFTIAN FILARIASIS EXPOSURE RATES IN CHILDREN AFTER TWELVE ROUNDS OF MASS DRUG ADMINISTRATION AND USE OF LONG-LASTING INSECTICIDAL NETS IN RUFIJI DISTRICT, TANZANIA

BackgroundTanzania started implementing the WHO strategy of mass drug administration (MDA) with ivermectin and albendazole to eliminate lymphatic filariasis (LF) in Rufiji District, which had a baseline prevalence of 49%...

A Comparative evaluation of diagnostic performance of Immunochromatographic Rapid Card Test for malarial antigen against Peripheral smear Microscopy

Background: Malaria poses a major public health problem in India and has emerged as a biggest health burden in terms of morbidity and mortality. Rapid detection of malarial parasite can ensure the prompt timely and efficient management of clinical cases and control of the disease. Objectives: To evaluate the diagnostic performance of Immunochromatographic Rapid Card Test (ICT) for malarial antigen against Peripheral smear microscopy for diagnosing Malaria. Materials and Methods : This Cross sectional study was conducted in Dept. of Microbiology of a Rural tertiary care teaching hospital of Western Uttar Pradesh from January 2016 to August 2016. Eight Hundred thirty seven patients with clinical suspicion of malaria whose samples were sent on advice by clinicians to the Microbiology laboratory for the peripheral smear microscopy and Rapid card test for malarial antigen were included in this study after obtaining clearance from Institutional Ethics committee. Results : Out of the 837 blood samples tested, 106(12.66%) samples tested positive for malaria by Peripheral smear microscopy and 109(13%) by ICT Rapid card tests. The sensitivity of ICT for non-falciparum malaria (82.65%) came out to be lower than that for falciparum malaria (87.5%). The specificity of ICT for non falciparum malaria (98.9%) was almost same as for falciparum malaria (99.3%).The accuracy of ICT for falciparum malaria (99.16%) was slightly higher than for non-falciparum malaria (97%). Conclusion: This study suggests that ICT Rapid card test couldnt replace PS microscopy completely, but can be used as an alternative or complimentary to microscopy, particularly in resource constrained remote rural areas of India.

Dynamics of antigenemia and transmission intensity of Wuchereria bancrofti following cessation of mass drug administration in a formerly highly endemic region of Mali.

BackgroundAfter seven annual rounds of mass drug administration (MDA) in six Malian villages highly endemic for Wuchereria bancrofti (overall prevalence rate of 42.7%), treatment was discontinued in 2008. Surveillance was performed over the ensuing 5 years to detect recrudescence.MethodsCirculating filarial antigen (CFA) was measured using immunochromatographic card tests (ICT) and Og4C3 ELISA in 6–7 year-olds. Antibody to the W. bancrofti infective larval stage (L3) antigen, Wb123, was tested in the same population in 2012. Microfilaraemia was assessed in ICT-positive subjects. Anopheles gambiae complex specimens were collected monthly using human landing catch (HLC) and pyrethrum spray catch (PSC). Anopheles gambiae complex infection with W. bancrofti was determined by dissection and reverse transcriptase polymerase chain reaction (RT-PCR) of mosquito pools.ResultsAnnual CFA prevalence rates using ICT in children increased over time from 0% (0/289) in 2009 to 2.7% (8/301) in 2011, 3.9% (11/285) in 2012 and 4.5% (14/309) in 2013 (trend χ 2 = 11.85, df =3, P = 0.0006). Wb123 antibody positivity rates in 2013 were similar to the CFA prevalence by ELISA (5/285). Although two W. bancrofti-infected Anopheles were observed by dissection among 12,951 mosquitoes collected by HLC, none had L3 larvae when tested by L3-specific RT-PCR. No positive pools were detected among the mosquitoes collected by pyrethrum spray catch. Whereas ICT in 6–7 year-olds was the major surveillance tool, ICT positivity was also assessed in older children and adults (8–65 years old). CFA prevalence decreased in this group from 4.9% (39/800) to 3.5% (28/795) and 2.8% (50/1,812) in 2009, 2011 and 2012, respectively (trend χ 2 = 7.361, df =2, P = 0.0067). Some ICT-positive individuals were microfilaraemic in 2009 [2.6% (1/39)] and 2011 [8.3% (3/36)], but none were positive in 2012 or 2013.ConclusionAlthough ICT rates in children increased over the 5-year surveillance period, the decrease in ICT prevalence in the older group suggests a reduction in transmission intensity. This was consistent with the failure to detect infective mosquitoes or microfilaraemia. The threshold of ICT positivity in children may need to be re-assessed and other adjunct surveillance tools considered.

Seropositivity of hepatitis b surface antigen in tertiary care centre: issues & considerations

Background: Hepatitis B virus (HBV) infects more than 300 million people worldwide and is common cause of liver disease and liver cancer. HBV, a member of the Hepadnaviridae family, is a small DNA virus with unusual features similar to retroviruses. HBV replicates through an RNA intermediate and can integrate into the host genome. The unique features of the HBV replication cycle confer a distinct ability of the virus to persist in infected cells. Aims & Objective: This study was designed to determine HBsAg Seropositivity among rural population attending inpatients and outpatients at tertiary care center with special consideration to childbearing age women. Material & Method: This retrospective study was conducted in the Department of Microbiology for three months in a tertiary care center catering rural population. A total of 1463 patients attending outdoor and indoor, were screened for HBsAg by lateral flow based rapid immunochromatographic card test (ICT) manufactured by J Mitra & Co Pvt Ltd. Results: Seropositivity of HBsAg was 41/1463(2.80%). Seropositivity was seen more in males 27/756(3.57%) as compared to females 14/707(1.98%). Age range 31-45 years was found to have highest prevalence rate with seropositivity of 15/279(5.38%). Among patients screened for HbsAg, we observed seropositivity of 2.37% (12/505) among women of childbearing age with age range 16 to 45 years. Conclusion: Findings in this study significantly contribute to the understanding of actual epidemiology of HBsAg in rural population especially women of childbearing age. Therefore, we should make efforts to prevent HBV infection by focusing on associated risk factors.

Positivity of Antigen Tests Used for Diagnosis of Lymphatic Filariasis in Individuals Without Wuchereria bancrofti Infection But with High Loa loa Microfilaremia

Since the mid-2000s, the immunochromatographic card test (ICT), a point-of-care test for detecting Wuchereria bancrofti circulating filarial antigens (CFAs), has been the backbone for mapping and monitoring lymphatic filariasis (LF) worldwide. Recently, there have been instances in which CFA positivity has been associated with Loa loa microfilaremia. Here, we examined the association, at both the community and individual levels, between L. loa and CFA using additional diagnostic tools (quantitative polymerase chain reaction [qPCR], Og4C3 enzyme-linked immunosorbent assay, and IgG4 antibodies to Wb123 assays) to demonstrate the relationship between L. loa microfilaremia and ICT positivity. In May 2013, peripheral blood was collected during the day from 1,812 individuals living in southern Cameroon. ICT tests were done on the spot, and positive individuals were resampled at night. Results of qPCR and Wb123 assays concurred proving the absence of W. bancrofti infection. Og4C3 assays indicate a quantitative relationship between the level of L. loa microfilaremia and that of CFA. This was confirmed by epidemiological analyses, which reveal a strong association between L. loa microfilaremia and ICT positivity, with 50% of ICT reacting to L. loa when its microfilarial density exceeds 30,000 microfilariae/mL. At the community level, the proportion of positive ICT would exceed 2% when the prevalence of L. loa microfilaremia in the total population is above 20%. This has significant implications in terms of mapping and control of LF caused by W. bancrofti in Loa-endemic areas. Cross-reactivity of ICT with L. loa has to be considered in the context of both individual and community diagnostics.

Does 24bp Duplication of Human CHIT1 Gene (Chitotriosidase1) Predispose to Filarial Chyluria? A Case-Control Study.

Chyluria which is endemic in many parts of the world is mainly caused by Wuchereria bancrofti. CHIT1 (chitotriosidase) is produced by macrophages and plays an important role in the defense against chitin containing pathogen such as filarial parasite. Variation in the coding region with 24 bp duplication allele results in reduced CHIT1 activity that enhance the survival of parasite which may play a role in the occurrence of disease. To examine the role of 24bp duplication of CHIT1 gene in patients of filarial chyluria (FC). A case-control study was carried out where 155 confirmed FC patients and equal number of age-, sex- and residence-matched controls without any symptoms or signs of lymphatic filariasis, confirmed by negative immunochromatographic card test (ICT) and IgG/IgM combo rapid antibody test, from a hospital-based population were enrolled. Filarial aetiology was confirmed on the basis of DEC-provocative test (Giemsa staining), ICT and IgG/IgM- antifiarial antibody test. The patients positive by either of these tests were enrolled as FC cases. 24bp duplication in CHIT1 gene in FC was detected by the product size 99bp of amplified gene using polymerase chain reaction. The mean ages of patients and controls were 38.25±12.09 and 35.45±12.53 years, respectively while male: female ratio was 2.4:1. The mean duration of illness in chyluria patients was 62.81±60.83 months and mean number of episodes was 2.54±1.11. Homozygous wild type, heterozygous and homozygous mutant frequencies were 10.3%, 81.3% and 8.4% in FC patients and 18.7%, 75.5%, and 5.8% in controls, respectively. The 24bp duplication in CHIT1 gene showed a significant association in Heterozygous (HT) genotype with Odd Ratio (OR) of 1.95, 95% Confidence Interval (CI) (1.01-3.77); p=0.04. However, the homozygous mutant genotype (TT) was found to be non-significant with OR of 2.61, 95% CI (0.91-7.45); p=0.07. The combination of both HT+TT was also found to be significant with OR of 2.00, 95% CI (1.03-3.85); p=0.03. In this study from Northern India, CHIT1 gene polymorphism showed an influence as a possible risk factor for susceptibility to FC. Further studies need to be done on a larger number of FC patients in different regions of the country.

Cross-Reactivity of Filariais ICT Cards in Areas of Contrasting Endemicity of Loa loa and Mansonella perstans in Cameroon: Implications for Shrinking of the Lymphatic Filariasis Map in the Central African Region.

BackgroundImmunochromatographic card test (ICT) is a tool to map the distribution of Wuchereria bancrofti. In areas highly endemic for loaisis in DRC and Cameroon, a relationship has been envisaged between high L. loa microfilaria (Mf) loads and ICT positivity. However, similar associations have not been demonstrated from other areas with contrasting levels of L. loa endemicity. This study investigated the cross-reactivity of ICT when mapping lymphatic filariasis (LF) in areas with contrasting endemicity levels of loiasis and mansonellosis in Cameroon.Methodology/Principal FindingsA cross-sectional study to assess the prevalence and intensity of W. bancrofti, L. loa and M. perstans was carried out in 42 villages across three regions (East, North-west and South-west) of the Cameroon rainforest domain. Diurnal blood was collected from participants for the detection of circulating filarial antigen (CFA) by ICT and assessment of Mf using a thick blood smear. Clinical manifestations of LF were also assessed. ICT positives and patients clinically diagnosed with lymphoedema were further subjected to night blood collection for the detection of W. bancrofti Mf. Overall, 2190 individuals took part in the study. Overall, 24 individuals residing in 14 communities were tested positive by ICT, with prevalence rates ranging from 0% in the South-west to 2.1% in the North-west. Lymphoedema were diagnosed in 20 individuals with the majority of cases found in the North-west (11/20), and none of them were tested positive by ICT. No Mf of W. bancrofti were found in the night blood of any individual with a positive ICT result or clinical lymphoedema. Positive ICT results were strongly associated with high L. loa Mf intensity with 21 subjects having more than 8,000 L. loa Mf ml/blood (Odds ratio = 15.4; 95%CI: 6.1–39.0; p < 0.001). Similarly, a strong positive association (Spearman’s rho = 0.900; p = 0.037) was observed between the prevalence of L. loa and ICT positivity by area: a rate of 1% or more of positive ICT results was found only in areas with an L. loa Mf prevalence above 15%. In contrast, there was no association between ICT positivity and M. perstans prevalence (Spearman’s rho = - 0.200; p = 0.747) and Mf density (Odds ratio = 1.8; 95%CI: 0.8–4.2; p = 0.192).Conclusions/SignificanceThis study has confirmed the strong association between the ICT positivity and L. loa intensity (Mf/ml of blood) at the individual level. Furthermore, the study has demonstrated that ICT positivity is strongly associated with high L. loa prevalence. These results suggest that the main confounding factor for positive ICT test card results are high levels of L. loa. The findings may indicate that W. bancrofti is much less prevalent in the Central African region where L. loa is highly endemic than previously assumed and accurate re-mapping of the region would be very useful for shrinking of the map of LF distribution.

Shrinking the Lymphatic Filariasis Map of Ethiopia: Reassessing the Population at Risk through Nationwide Mapping.

BackgroundMapping of lymphatic filariasis (LF) is essential for the delineation of endemic implementation units and determining the population at risk that will be targeted for mass drug administration (MDA). Prior to the current study, only 116 of the 832 woredas (districts) in Ethiopia had been mapped for LF. The aim of this study was to perform a nationwide mapping exercise to determine the number of people that should be targeted for MDA in 2016 when national coverage was anticipated.Methodology/Principal FindingA two-stage cluster purposive sampling was used to conduct a community-based cross-sectional survey for an integrated mapping of LF and podoconiosis, in seven regional states and two city administrations. Two communities in each woreda were purposely selected using the World Health Organization (WHO) mapping strategy for LF based on sampling 100 individuals per community and two purposely selected communities per woreda. Overall, 130 166 people were examined in 1315 communities in 658 woredas. In total, 140 people were found to be positive for circulating LF antigen by immunochromatographic card test (ICT) in 89 communities. Based on WHO guidelines, 75 of the 658 woredas surveyed in the nine regions were found to be endemic for LF with a 2016 projected population of 9 267 410 residing in areas of active disease transmission. Combining these results with other data it is estimated that 11 580 010 people in 112 woredas will be exposed to infection in 2016.ConclusionsWe have conducted nationwide mapping of LF in Ethiopia and demonstrated that the number of people living in LF endemic areas is 60% lower than current estimates. We also showed that integrated mapping of multiple NTDs is feasible and cost effective and if properly planned, can be quickly achieved at national scale.

Modelling the distribution and transmission intensity of lymphatic filariasis in sub-Saharan Africa prior to scaling up interventions: integrated use of geostatistical and mathematical modelling.

BackgroundLymphatic filariasis (LF) is one of the neglected tropical diseases targeted for global elimination. The ability to interrupt transmission is, partly, influenced by the underlying intensity of transmission and its geographical variation. This information can also help guide the design of targeted surveillance activities. The present study uses a combination of geostatistical and mathematical modelling to predict the prevalence and transmission intensity of LF prior to the implementation of large-scale control in sub-Saharan Africa.MethodsA systematic search of the literature was undertaken to identify surveys on the prevalence of Wuchereria bancrofti microfilaraemia (mf), based on blood smears, and on the prevalence of antigenaemia, based on the use of an immuno-chromatographic card test (ICT). Using a suite of environmental and demographic data, spatiotemporal multivariate models were fitted separately for mf prevalence and ICT-based prevalence within a Bayesian framework and used to make predictions for non-sampled areas. Maps of the dominant vector species of LF were also developed. The maps of predicted prevalence and vector distribution were linked to mathematical models of the transmission dynamics of LF to infer the intensity of transmission, quantified by the basic reproductive number (R0).ResultsThe literature search identified 1267 surveys that provide suitable data on the prevalence of mf and 2817 surveys that report the prevalence of antigenaemia. Distinct spatial predictions arose from the models for mf prevalence and ICT-based prevalence, with a wider geographical distribution when using ICT-based data. The vector distribution maps demonstrated the spatial variation of LF vector species. Mathematical modelling showed that the reproduction number (R0) estimates vary from 2.7 to 30, with large variations between and within regions.ConclusionsLF transmission is highly heterogeneous, and the developed maps can help guide intervention, monitoring and surveillance strategies as countries progress towards LF elimination.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1166-x) contains supplementary material, which is available to authorized users.

The Impact of Six Annual Rounds of Mass Drug Administration on Wuchereria bancrofti Infections in Humans and in Mosquitoes in Mali.

Wuchereria bancrofti prevalence and transmission were assessed in six endemic villages in Sikasso, Mali prior to and yearly during mass drug administration (MDA) with albendazole and ivermectin from 2002 to 2007. Microfilaremia was determined by calibrated thick smear of night blood in adult volunteers and circulating filarial antigen was measured using immunochromatographic card test in children < 5 years of age. Mosquitoes were collected by human landing catch from July to December. None of the 686 subjects tested were microfilaremic 12 months after the sixth MDA round. More importantly, circulating antigen was not detected in any of the 120 children tested, as compared with 53% (103/194) before the institution of MDA. The number of infective bites/human/year decreased from 4.8 in 2002 to 0.04 in 2007, and only one mosquito containing a single infective larva was observed 12 months after the final MDA round. Whether this dramatic reduction in transmission will be sustained following cessation of MDA remains to be seen.

Evidence of continued transmission of Wuchereria bancrofti and associated factors despite nine rounds of ivermectin and albendazole mass drug administration in Rufiji district, Tanzania

Background: In most sub-Saharan Africa, the National Lymphatic Filariasis Elimination Programme (NLFEP) is based on annual mass drug administration (MDA) with ivermectin and albendazole. In order to interrupt transmission, 4–6 rounds of MDA are required with at least 60–70% minimum effective coverage. Children born since the introduction of the MDA programme are recommended for assessing the interruption of transmission. The objective of this study was lymphatic filariasis transmission status after nine rounds of MDA in Rufiji district, Tanzania. Methods : This cross sectional survey involved 270 heads of household. Parents or guardians were interviewed on behalf of the schoolchildren about their participation in MDA programme. Status of LF prevalence was assessed by measuring Wuchereria bancrofti circulating filarial antigens (CFA) in blood samples from standard one school children (6 – 9 years) using immunochromatographic test cards. Results: A total of 413 standard one schoolchildren were tested for CFA; 59 (14.3%) had CFA. Two thirds (66.8%) of the children did not participate in 2011 MDA round. Prevalence of CFA was significantly lower in younger (6.4%) than older children (40.4%) (p<0.05). Participation in the last (2011) MDA did not significantly change the prevalence W. bancrofti CFA (χ 2 = 0.723, p=0.4). The recorded MDA coverage for 5 years including 2011 was above the 60–70 % minimum effective coverage. The community reported coverage was 40.4% for last MDA (2011), for previous MDAs was 53.0%; being far below the minimum effective coverage. Though the large majority (97.0%) of households had heard of LF, only about half (57.0%) knew it was transmitted by mosquitoes. Less than a half (43.6%) of households were aware of the adverse effects of LF, therefore motivated to participate in MDA. Conclusion: The findings indicate that LF transmission has continued in Rufiji district despite nine rounds of MDA. Low compliance to MDAs due to community and programmatic factors were responsible for the continued LF transmission. Detailed entomological studies are required to establish LF transmission dynamics and the programmatic factors associated with MDA implementation in the area.

The utility of syphilis point-of-care testing in remote Queensland communities

The rate of infection with syphilis has been steadily climbing over the past ten years Australia-wide. Remote areas of North Queensland have also experienced a dramatic increase in infection, with a concomitant increase in cases of congenital syphilis. Geographically remote locations pose difficulties with respect to specimen transport, processing, and turnaround time. Point-of-care testing (PoCT) offers a practical solution to many of these issues, though it is not a panacea. We aimed to assess the role of syphilis PoCT for remote areas in North Queensland. Throughout 2013–2014 we performed PoCT on field and stored specimens using the SD Bioline Syphilis 3.0 and the Chembio DPP Syphilis Screen and Confirm Assay. Both assays are immunochromatographic card tests, but the Chembio assay detects both non-treponemal and treponemal antibodies. Results were compared to gold standard testing. While both tests are convenient and easy to read, neither is sufficiently sensitive nor specific to replace the gold standard of formal treponemal testing. This is especially true in areas with a low prevalence of disease. Currently our recommendation is that all patients at high risk of infection should be assessed with gold standard testing, even in the presence of a negative point-of-care test. The rate of infection with syphilis has been steadily climbing over the past ten years Australia-wide. Remote areas of North Queensland have also experienced a dramatic increase in infection, with a concomitant increase in cases of congenital syphilis. Geographically remote locations pose difficulties with respect to specimen transport, processing, and turnaround time. Point-of-care testing (PoCT) offers a practical solution to many of these issues, though it is not a panacea. We aimed to assess the role of syphilis PoCT for remote areas in North Queensland. Throughout 2013–2014 we performed PoCT on field and stored specimens using the SD Bioline Syphilis 3.0 and the Chembio DPP Syphilis Screen and Confirm Assay. Both assays are immunochromatographic card tests, but the Chembio assay detects both non-treponemal and treponemal antibodies. Results were compared to gold standard testing. While both tests are convenient and easy to read, neither is sufficiently sensitive nor specific to replace the gold standard of formal treponemal testing. This is especially true in areas with a low prevalence of disease. Currently our recommendation is that all patients at high risk of infection should be assessed with gold standard testing, even in the presence of a negative point-of-care test.

Lymphatic filariasis transmission assessment survey in schools three years after stopping mass drug treatment with albendazole and ivermectin in the 7 endemic districts in Togo

The aim of this study is to verify the level of transmission of lymphatic filariasis three years after stopping mass drug treatment in the 7 endemic districts in Togo. The survey was conducted in 2012 in Togo's 7 endemic districts grouped into four evaluation units (EU) using the WHO-recommended transmission assessment survey (TAS) protocol. Children aged 6-7 years were screened for Wuchereria bancofti antigen using the immunochromatographic card (ICT) method. A cluster sampling method was used to select eligible children in schools as the net primary-school enrolment ratio is greater than or equal to 75% in each of the four EUs. The number of children and schools to be selected in each EU, the randomization list for the selection of these children and the critical cut-off number of positive cases not to exceed were automatically generated using the Survey Sample Builder (SSB) tool, (NTD Support Center, Atlanta, Ga, USA). For confirmation, positive cases were subsequently tested for microfilaremia using nocturnal thick blood smear and for filarial antigen using Og4C3 antigen ELISA (TropBio ELISA Kit®, Townsville, Queensland, Australia). An EU is considered to have passed the test successfully (it is assumed that transmission can no longer be sustained), when the number of positive cases is below the critical cut-off number set by the SSB, which is roughly equivalent to 2% prevalence. Of the 1 706 children surveyed in Kpendjal-Tone's EU, 1 549 in Binah-Doufelgou's EU, 1 550 in Kozah's EU and the 1 575 in Amou-Haho's EU, 8 (0.46%), 1 (0.08%), 0 (0.00%) and 4 (0.25%) ICT positive cases respectively were detected. The number of positive ICT tests was well below 18, the critical cut number for each of the 4 EUs. All 13 ICT positive cases tested negative for nocturnal microfilaremia and Og4C3 ELISA. We conclude that all four EU passed the TAS with success, and the transmission of Wuchereria bancrofti is no longer likely to be sustained in the 7 endemic districts in Togo 3 years after stopping the MDA. A new TAS will be carried out in 2015, after which, if the results are still good, the country will submit a dossier to WHO for verification of the elimination of lymphatic filariasis.

Epidemiology and individual, household and geographical risk factors of podoconiosis in Ethiopia: results from the first nationwide mapping.

Although podoconiosis is one of the major causes of tropical lymphoedema and is endemic in Ethiopia its epidemiology and risk factors are poorly understood. Individual-level data for 129,959 individuals from 1,315 communities in 659 woreda (districts) were collected for a nationwide integrated survey of lymphatic filariasis and podoconiosis. Blood samples were tested for circulating Wuchereria bancrofti antigen using immunochromatographic card tests. A clinical algorithm was used to reach a diagnosis of podoconiosis by excluding other potential causes of lymphoedema of the lower limb. Bayesian multilevel models were used to identify individual and environmental risk factors. Overall, 8,110 of 129,959 (6.2%, 95% confidence interval [CI] 6.1–6.4%) surveyed individuals were identified with lymphoedema of the lower limb, of whom 5,253 (4.0%, 95% CI 3.9–4.1%) were confirmed to be podoconiosis cases. In multivariable analysis, being female, older, unmarried, washing the feet less frequently than daily, and being semiskilled or unemployed were significantly associated with increased risk of podoconiosis. Attending formal education and living in a house with a covered floor were associated with decreased risk of podoconiosis. Podoconiosis exhibits marked geographical variation across Ethiopia, with variation in risk associated with variation in rainfall, enhanced vegetation index, and altitude.