A large-scale field randomized trial demonstrates safety and efficacy of the vaccine LetiFend® against canine leishmaniosis.

Observations are reported on diapause and laboratory breeding of Phlebotomus perniciosus Newst. and P. ariasi Tonnoir, the two phlebotomine sandflies incriminated as vectors of visceral leishmaniasis in southern France. Previous field studies had suggested that both species are univoltine in southern France, but the present laboratory investigations showed that diapause is obligatory for neither species. Temperature (both species) and photoperiod (P. perniciosus) were found to affect diapause-induction, and diapause was commonly determined before the overwintering stage (the fourth-instar larva). The results showed that P. perniciosus can be mass-reared for at least three uninterrupted generations each year if it is maintained at 28°C in LD 17:7. Further investigations are needed if P. ariasi is also to be bred in sufficient numbers for epidemiological experiments; its colonisation was prevented primarily by low fertility, and attempts at forced insemination were unsuccessful.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0007485300007793

Diapause and laboratory breeding of Phlebotomus perniciosus Newstead and Phlebotomus ariasi Tonnoir (Diptera: Psychodidae) from southern France

Background: Visceral leishmaniasis due to Leishmania infantum is currently spreading into new foci across Europe. Leishmania infantum transmission in the Old World was reported to be strongly associated with a few specific environments. Environmental changes due to global warming or human activity were therefore incriminated in the spread of the disease. However, comprehensive studies were lacking to reliably identify all the environments at risk and thereby optimize monitoring and control strategy. Methodology/Findings: We exhaustively collected 328 cases of autochthonous visceral leishmaniasis from 1993 to 2009 in SouthEastern France. Leishmaniasis incidence decreased from 31 yearly cases between 1993 and 1997 to 12 yearly cases between 2005 and 2009 mostly because Leishmania/HIV coinfection were less frequent. No spread of human visceral leishmaniasis was observed in the studied region. Two major foci were identified, associated with opposite environments: whereas one involved semi-rural hillside environments partly made of mixed forests, the other involved urban and peri-urban areas in and around the region main town, Marseille. The two neighboring foci were related to differing environments despite similar vectors (P. perniciosus), canine reservoir, parasite (L. infantum zymodeme MON-1), and human host. Conclusions/Significance: This unprecedented collection of cases highlighted the occurrence of protracted urban transmission of L. infantum in France, a worrisome finding as the disease is currently spreading in other areas around the Mediterranean. These results complete previous studies about more widespread canine leishmaniasis or human asymptomatic carriage. This first application of systematic geostatistical methods to European human visceral leishmaniasis demonstrated an unsuspected heterogeneity of environments associated with the transmission of the disease. These findings modify the current view of leishmaniasis epidemiology. They notably stress the need for locally defined control strategies and extensive monitoring including in urban environments.

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Heterogeneity of environments associated with transmission of visceral leishmaniasis in South-Eastern France and implication for control strategies.

Leishmania infantum is the only species occurring in metropolitan France; located in the Mediterranean part of the country, it is responsible for a highly enzootic canine disease, while the human endemicity is low, with about 23 cases yearly reported to the National Reference Centre of Leishmaniases, mainly visceral forms. In French Guyana, five Leishmania species occur in the Amazonian forest, of which L. guyanensis is the predominant species, and L. braziliensis is responsible for the most critical forms. The most frequent clinical feature is cutaneous leishmaniasis, with a mean annual incidence reaching 2 p. 1000, with some inter-annual fluctuations. In Martinique Island, recent studies have confirmed the presence of an ancestral Leishmania species, responsible for small cutaneous lesions, of mild evolution; the life cycle of this species remains unknown. In Guadeloupe Island, a few autochthonous visceral leishmaniasis cases have been reported, needing a prospective study.

Épidémiologie des leishmanioses autochtones en France métropolitaine et d’outre-mer

Resume Deux cas autochtones de leischmaniose humaine ont ete signales en Auvergne. Le nombre croissant de chiens leishmaniens en transit, comme la pullulation des phlebotomes au cours de l'ete, dans certaines localites de Limagne sont en faveur d'une transmission locale.

Ranque J

Papers

[Leishmaniasis in south-eastern France- -ecology, epidemiology, prophylaxis].