Search

To shed first light on caprine schistosomiasis and its zoonotic potential in Malawi, we conducted a molecular epidemiological investigation, sampling goats ( n  = 230) across three districts, using faecal miracidia hatching test. Molecular genotyping of miracidia later revealed the prevalence of Schistosoma mattheei to be 0.0 % in Nsanje District ( n  = 30), 16.7 % in Chikwawa District (n = 30) and 25.3 % in Mangochi District ( n  = 170). Notably, a miracidium of Schistosoma haematobium was observed from a single goat in Chikwawa. Inspection of carcasses ( n  = 51) at two local abattoirs in Mangochi District did not find any evidence of caprine schistosomiasis where only a single herd, at Mangochi 3, was infected. Here, despite sampling several other herds nearby, the prevalence was 87.7 % ( n  = 49), with an animal found excreting 1000 miracidia per 5 g of faeces. At this location, our praziquantel treatment ( n  = 14) and GPS animal tracking ( n  = 2) pilot sub-study compared two local goat herds over a three-month period. The daily foraging ranges across a 10 km 2 area were recorded, alongside targeted schistosome surveillance within local freshwater intermediate snail hosts. Analysis of GPS data revealed only one herd (infected) to have regular daily water contact with Lake Malawi whereas the other herd (not infected) totally avoided the lake. One week after praziquantel treatment administered at 40 mg/kg, anthelminthic cure rate was 92.3 % while at three months approximately a third of treated animals were shedding schistosome miracidia. Cercariae from several field-caught snails locally were genotyped, inclusive of finding a Schistosoma haematobium - mattheei hybrid. Our findings reveal the focalized nature of caprine schistosomiasis, signposting a novel alert for S. haematobium transmission, and highlight where zoonotic transmission can be intense. To better address zoonotic spill-over from S. mattheei (and/or S. haematobium ), the national control programme for schistosomiasis should formally develop targeted surveillance of caprine schistosomiasis and where appropriate, attempt an integrated One Health intervention in future., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s). Published by Elsevier B.V.)

Background: Male Genital Schistosomiasis (MGS) remains an often-overlooked chronic sequela of urogenital schistosomiasis in endemic areas of sub-Saharan Africa. As part of a 2-year longitudinal study on Hybridization of UroGenital Schistosomiasis (HUGS) in Malawi, a MGS sub-study was conducted to assess whether hybrid schistosomes were incriminated., Methods: During recruitment, demographic, health and socio-economic data were collected through individual questionnaire interviews in Mthawira community from Nsanje District along Shire River and Samama community from Mangochi District along Lake Malawi shoreline. Urine and semen samples were collected and analysed to determine the identity of schistosome infection. Urine filtration and microscopy, direct microscopy of semen and its sediments (after centrifugation) were performed. Thereafter, the sediments were examined by molecular DNA analysis with a novel two-tube real-time PCR assay. The participants were also screened for Human papilloma virus (HPV) and other sexually transmitted infections (STIs)., Results: Twenty-two men were recruited for the sub-study, 8 in Nsanje District and 14 in Mangochi District, with a median age of 22.0 years. By microscopy, ten (45.7%) participants had Schistosoma ova in their urine, 11 (50.0%) in semen while 16 (72.7%) were positive by real-time PCR. One participant had both S. haematobium and S. mattheei ova in his semen, three showed symptoms, and one had a mixed infection of S. mansoni and possible S. haematobium-S. mattheei hybrid. Twelve men had detectable high-risk HPV serotypes 16, 18 and others while six had Trichomonas vaginalis and other STIs., Conclusion: Zoonotic and hybrid schistosomes can cause MGS similar to human schistosomes, which can be co-infected with HPV and STIs, thereby posing a new challenge in diagnosis, management and control measures in resource poor settings. Increased awareness of these infections among local communities and primary healthcare workers and improvement of disease management are needed and advocated., (© 2024. The Author(s).)

In Malawi, the putative origin of a newly described Schistosoma haematobium - mattheei hybrid human schistosome was assessed upon a seminal molecular parasitological survey of cattle. Using miracidia hatch test (MHT) and carcass inspection at slaughter, mean prevalence of bovine schistosomiasis was 49.1% (95% CI: 43.7-54.6%) and 10.3% (95% CI: 6.0-16.2%) respectively, though significant spatial heterogeneity was noted. Approximately 2.0% of infected cattle, and only those from Mangochi District, shed S. haematobium - mattheei and/or S. haematobium in faeces. To quantify schistosome (re)infection dynamics, where a S. haematobium - mattheei hybrid was present, we undertook a novel pilot GPS-datalogging sub-study within a specific herd of cattle ( n  = 8) on the Lake Malawi shoreline, alongside a praziquantel (40 mg/kg) treatment efficacy spot check. At sub-study baseline, all GPS-tagged cattle had proven daily water contact with the lake. Each animal was patently infected upon MHT, with older animals shedding less miracidia. At one month review, whilst parasitological cure was 100.0%, from six weeks onwards, (re)infection was first noted in the youngest animal. By three-month review, all animals were patently (re)infected though only miracidia of S. mattheei were recovered, albeit in much lower numbers. To conclude, infection with S. mattheei is particularly common in cattle and demonstrates a previously cryptic burden of bovine schistosomiasis. Within Mangochi District, bovine transmission of both S. haematobium - mattheei hybrids and S. haematobium are now incriminated, with unequivocal evidence of contemporary zoonotic spill-over. Future control of urogenital schistosomiasis here in the southern region needs to develop, then successfully integrate, a One Health approach with appropriate mitigating strategies to reduce and/or contain bovine schistosomiasis transmission., Competing Interests: The authors report no conflicts of interest., (© 2024 The Authors.)