National mapping of schistosomiasis, soil-transmitted helminthiasis and anaemia in Yemen: Towards better national control and elimination.

BACKGROUND: Schistosomiasis (SCH) and soil-transmitted helminthiasis (STH) are known to be endemic in Yemen. However, the distribution of both diseases had not previously been assessed by a well-structured national mapping study covering all governorates. The main aim of this study was, therefore, to map the prevalence of SCH and STH in Yemen in order to better inform implementation of effective national control and elimination interventions. The assessment of the distribution of anaemia was also included as a well-known consequence of infection with both SCH and STH. Secondarily, the study aimed to provide a broad indication of the impact of large-scale treatment on the distribution of infection. METHODOLOGY AND PRINCIPAL FINDINGS: To achive these aims, 80,432 children (10-14 years old) from 2,664 schools in 332 of Yemen's 333 districts were included, in 2014, into this national cross-sectional survey. Countrywide, 63.3% (210/332) and 75.6% (251/332) of districts were found to be endemic for SCH and STH respectively. More districts were affected by intestinal than urogenital SCH (54.2% and 31.6% respectively). SCH infection was mostly mild and moderate, with no districts reporting high infection. One quarter (24.4%) of Yemeni districts had high or moderate levels of Ascaris lumbricoides infection. Infection with Trichuris trichiura was the second most common STH (44.9% of districts infected) after A. lumbricoides (68.1%). Hookworm was the least prevalent STH (9.0%). Anaemia was prevalent in 96.4% of districts; it represented a severe public health problem (prevalence ≥ 40%) in 26.5% of districts, and a mild to moderate problem in two thirds of the districts (33.7% and 36.1% respectively). CONCLUSION: This study provided the first comprehensive mapping of SCH, STH, and anaemia across the country. This formed the basis for evaluating and continuing the national control and elimination programme for these neglected tropical diseases in Yemen.

First detection of Leishmania DNA in Psammomys obesus and Psammomys vexillaris: Their potential involvement in the epidemiology of leishmaniasis in Tunisia.

Leishmaniasis, a public health problem in Tunisia, are diseases caused by different Leishmania species. Cutaneous leishmaniasis is present from the North to the South under different forms, due to Leishmania (L.) major, L. infantum or L. tropica. Whereas, Psammomys (P.) obesus is the confirmed reservoir host of L. major, those of L. tropica and dermotropic L. infantum wait to be identified. Importantly, P. vexillaris species have been recently highlighted; however, no studies have been carried out to explore its potential role in leishmaniasis epidemiology. Seventy two rodents were collected from Central and South-West of Tunisia between 2007 and 2010. Using several methods, 43 animals were identified as P. obesus and 29 as P. vexillaris. Leishmania kinetoplast DNA was detected in liver samples by real-time PCR in 18 P. obesus and in 8 P. vexillaris. Then, the direct sequencing of the amplified internal transcribed spacer 1, allowed the identification of L. infantum DNA in five P. obesus and in three P. vexillaris, as well as L. tropica DNA in three other P. vexillaris. Whereas, PCR fluorescent fragment length analysis of the 7 spliced leaders, allowed identifying L. major among infected P. obesus and P. vexillaris, and interestingly co-infection (L. major/L. infantum) among two P. obesus. We report here for the first time, the infection of P. obesus, from Central Tunisia, by L. infantum. Suggesting that P. obesus the known reservoir host of L. major, may also serve as reservoir host for L. infantum and thus play a role in the spread of sporadic cutaneous or visceral leishmaniasis in this region. Of equal importance, this work establish for the first time, the natural infection of P. vexillaris by different Leishmania species, suggesting its potential epidemiological role as reservoir host.

Evaluation of a gp63-PCR based assay as a molecular diagnosis tool in canine leishmaniasis in Tunisia.

A gp63PCR method was evaluated for the detection and characterization of Leishmania (Leishmania) (L.) parasites in canine lymph node aspirates. This tool was tested and compared to other PCRs based on the amplification of 18S ribosomal genes, a L. infantum specific repetitive sequence and kinetoplastic DNA minicircles, and to classical parasitological (smear examination and/or culture) or serological (IFAT) techniques on a sample of 40 dogs, originating from different L. infantum endemic regions in Tunisia. Sensitivity and specificity of all the PCR assays were evaluated on parasitologically confirmed dogs within this sample (N = 18) and control dogs (N = 45) originating from non-endemic countries in northern Europe and Australia. The gp63 PCR had 83.5% sensitivity and 100% specificity, a performance comparable to the kinetoplast PCR assay and better than the other assays. These assays had comparable results when the gels were southern transferred and hybridized with a radioactive probe. As different infection rates were found according to the technique, concordance of the results was estimated by (κ) test. Best concordance values were between the gp63PCR and parasitological methods (74.6%, 95% confidence intervals CI: 58.8-95.4%) or serology IFAT technique (47.4%, 95% CI: 23.5-71.3%). However, taken together Gp63 and Rib assays covered most of the samples found positive making of them a good alternative for determination of infection rates. Potential of the gp63PCR-RFLP assay for analysis of parasite genetic diversity within samples was also evaluated using 5 restriction enzymes. RFLP analysis confirmed assignment of the parasites infecting the dogs to L. infantum species and illustrated occurrence of multiple variants in the different endemic foci. Gp63 PCR assay thus constitutes a useful tool in molecular diagnosis of L. infantum infections in dogs in Tunisia.

Towards nationwide control of schistosomiasis in Yemen: a pilot project to expand treatment to the whole community.

Both the urinary and intestinal forms of schistosomiasis are thought to be widespread in the Republic of Yemen, with estimates of 3 million people infected and 600 000 suffering clinical morbidity. Sub-national control has been ongoing since 2006 via the distribution of praziquantel (PZQ) against schistosomiasis and albendazole (ALB) against soil-transmitted helminths using school-based treatment. In preparation for a 6-year nationwide control programme with the aim of expanding treatment to the wider community, a new programmatic approach of complementing school-based distribution with community-based treatment was trialled in 10 highly endemic districts in three governorates in December 2009. The new approach achieved coverage of 90.1% of non-enrolled children: a 40% increase compared with the same districts in 2008, and coverage of 97.9% of enrolled children: a 2% increase compared to 2008. Coverage of females (children and adults) was 81.8%, and of adults in general was 73.9%. The total cost per person treated was US$0.66 (US$0.79 in 2008), which includes training, health education, social mobilization, distribution and drugs. These results provide hope that a combined school and community-based approach can be successfully implemented on a wider scale during the main control programme in 2010-2015, with approximately 10 million people targeted in the first year alone.

Natural infection of Phlebotomus (Larroussius) langeroni (Diptera: Psychodidae) with Leishmania infantum in Tunisia.

Phlebotomine sand flies were captured from an active transmission focus of sporadic cutaneous leishmaniasis, caused by Leishmania infantum, in El Kef region, northern Tunisia. Both Phlebotomus perniciosus and P. langeroni were found. Phlebotomus langeroni females showed a statistically significant intradomiciliary dominance (P<0.01 for the 2003 and 2004 seasons) when compared to animal shelters. During the 2003 season, dissection of collected female specimens showed the presence of flagellates within the digestive tracts of two P. perniciosus among 1086 observed, but none in 232 P. langeroni. Amplification of kinetoplast minicircles of Leishmania parasites was applied to DNA samples extracted from 298 frozen females including 249 P. perniciosus, 36 P. langeroni, 5 P. longicuspis and 8 P. perfiliewi and revealed by radioactive probe hybridization. Two P. langeroni females showed a signal of the size expected for L. infantum (800bp) indicating infection with these parasites. However, this PCR-hybridization method failed to identify any positive P. perniciosus females in pools of specimens. These results show for the first time the natural infection of P. langeroni with L. infantum in Tunisia, and support the existence of different L. infantum transmission cycles in Tunisia, with a potential role for P. langeroni as a vector.