One Health Action against Human Fascioliasis in the Bolivian Altiplano: Food, Water, Housing, Behavioural Traditions, Social Aspects, and Livestock Management Linked to Disease Transmission and Infection Sources.

The Northern Bolivian Altiplano is the fascioliasis endemic area with the reported highest human prevalence and intensities. A multidisciplinary One Health initiative was implemented to decrease infection/reinfection rates detected by periodic monitoring between the ongoing yearly preventive chemotherapy campaigns. Within a One Health axis, the information obtained throughout 35 years of field work on transmission foci and affected rural schools and communities/villages is analysed. Aspects linked to human infection risk are quantified, including: (1) geographical extent of the endemic area, its dynamics, municipalities affected, and its high strategic importance; (2) human population at risk, community development and mortality rates, with emphasis on problems in infancy and gender; (3) characteristics of the freshwater collections inhabited by lymnaeid snail vectors and constituting transmission foci; (4) food infection sources, including population surveys with questionnaire and reference to the most risky edible plant species; (5) water infection sources; (6) household characteristics; (7) knowledge of the inhabitants on Fasciola hepatica and the disease; (8) behavioural, traditional, social, and religious aspects; (9) livestock management. This is the widest and deepest study of this kind ever performed. Results highlight prevention and control difficulties where inhabitants follow century-old behaviours, traditions, and beliefs. Intervention priorities are proposed and discussed.

Spread of the fascioliasis endemic area assessed by seasonal follow-up of rDNA ITS-2 sequenced lymnaeid populations in Cajamarca, Peru.

Fascioliasis is a worldwide emerging snail-borne zoonotic trematodiasis with a great spreading capacity linked to animal and human movements, climate change, and anthropogenic modifications of freshwater environments. South America is the continent with more human endemic areas caused by Fasciola hepatica, mainly in high altitude areas of Andean regions. The Peruvian Cajamarca area presents the highest human prevalences reported, only lower than those in the Bolivian Altiplano. Sequencing of the complete rDNA ITS-2 allowed for the specific and haplotype classification of lymnaeid snails collected in seasonal field surveys along a transect including 2007-3473 m altitudes. The species Galba truncatula (one haplotype preferentially in higher altitudes) and Pseudosuccinea columella (one haplotype in an isolated population), and the non-transmitting species Lymnaea schirazensis (two haplotypes mainly in lower altitudes) were found. Climatic seasonality proved to influence G. truncatula populations in temporarily dried habitats, whereas L. schirazensis appeared to be more climatologically independent due to its extreme amphibious ecology. Along the southeastern transect from Cajamarca city, G. truncatula and L. schirazensis shared the same site in 7 localities (46.7% of the water collections studied). The detection of G. truncatula in 11 new foci (73.3%), predominantly in northern localities closer to the city, demonstrate that the Cajamarca transmission risk area is markedly wider than previously considered. Lymnaea schirazensis progressively increases its presence when moving away from the city. Results highlight the usefulness of lymnaeid surveys to assess borders of the endemic area and inner distribution of transmission foci. Similar lymnaeid surveys are still in need to be performed in the wide northern and western zones of the Cajamarca city. The coexistence of more than one lymnaeid transmitting species, together with a morphologically indistinguishable non-transmitting species and livestock movements inside the area, conform a complex scenario which poses difficulties for the needed One Health control intervention.

One Health initiative in the Bolivian Altiplano human fascioliasis hyperendemic area: Lymnaeid biology, population dynamics, microecology and climatic factor influences / Aplicação do conceito One Health na área hiperendêmica de fasciolíase humana do Altiplano Boliviano: biologia dos limneídeos, dinâmica populacional, microecologia e influência de fatores climáticos

Abstract Fascioliasis is a freshwater snail-borne zoonotic disease. The Northern Bolivian Altiplano is a very high altitude endemic area where the highest human prevalences and intensities have been reported. Preventive chemotherapy by treatment campaigns is yearly applied. However, liver fluke infection of cattle, sheep, pigs and donkeys assures endemicity and consequent human infection and re-infection risks. A One Health action has therefore been implemented. Activity concerns lymnaeid vectors and environment diversity. Studies included growth, egg-laying and life span in laboratory-reared lymnaeids. Different habitat types and influencing factors were assessed. All populations proved to belong to Galba truncatula by rDNA sequencing. Analyses comprised physico-chemical characteristics and monthly follow-up of water temperature, pH and quantity, and lymnaeid abundance and density. Population dynamics in the transmission foci differed. Mean environmental temperature was lower than fluke development minimum temperature threshold, but water temperature was higher, except during winter. A two generations/year pattern appeared in permanent water habitats, and one generation/year pattern in habitats drying out for months. The multidisciplinary control measures can be extended from one part of the endemic area to another. These studies, made for the first time at very high altitude, constitute a baseline useful for fascioliasis control in other countries.

Resumo A fasciolíase é uma doença zoonótica transmitida para os humanos por formas evolucionárias de Fasciola hepatica oriundas de limneídeos infectados. O Altiplano Boliviano Norte é uma área endêmica de altitude muito alta, onde foram relatadas as maiores prevalências e intensidades em infecções humanas. A quimioterapia preventiva por campanhas de tratamento é aplicada anualmente. No entanto, infecção por Fasciola hepatica em bovinos, ovelhas, suínos e asininos garante endemicidade e consequentes riscos de infecção e reinfecção humana. Portanto, ações norteadas no conceito "One Health" foram implementadas. As atividades envolveram os limneídeos e a avaliação da diversidade de ambientes. Os estudos incluíram o crescimento, postura de ovos e expectativa de vida de limneídeos criados em laboratório, bem como a avaliação da influência dos diferentes hábitats. Todas as populações foram identificadas como Galba truncatula por meio do sequenciamento de rDNA. As análises incluíram características físico-químicas e acompanhamento mensal da temperatura, pH, quantidade da água, abundância e densidade de limneídeos. A dinâmica populacional nos focos de transmissão diferiu. A temperatura ambiente média foi mais baixa do que o limite mínimo de temperatura do desenvolvimento do helminto, mas a temperatura da água foi mais alta, exceto durante o inverno. Um padrão de duas gerações/ano apareceu em hábitats com água permanente, enquanto um padrão de uma geração/ano foi observado em habitats que ficam secos durante meses. Os resultados permitem concluir que as medidas multidisciplinares de controle podem ser estendidas de uma parte da área endêmica para outra. Esses estudos, realizados pela primeira vez em altitudes muito elevadas, constituem uma base útil e extrapolável para o controle da fasciolíase.