Visceral leishmaniasis (VL) is a systemic protozoan disease that is transmitted by phlebotomine sandflies. Poor and neglected populations in East Africa and the Indian sub-continent are particularly affected. Early and accurate diagnosis and treatment remain key components of VL control. In addition to improved diagnostic tests, accurate and simple tests are needed to identify treatment failures. Miltefosine, paromomycin and liposomal amphotericin B are gradually replacing pentavalent antimonials and conventional amphotericin B as the preferred treatments in some regions, but in other areas these drugs are still being evaluated in both mono- and combination therapies. New diagnostic tools and new treatment strategies will only have an impact if they are made widely available to patients.

http://www.bio.umass.edu/micro/klingbeil/590s/Reading/Leishdiag2007.pdf

Visceral leishmaniasis: what are the needs for diagnosis, treatment and control?

Phlebotomine sandflies transmit pathogens that affect humans and animals worldwide. We review the roles of phlebotomines in the spreading of leishmaniases, sandfly fever, summer meningitis, vesicular stomatitis, Chandipura virus encephalitis and Carrion's disease. Among over 800 species of sandfly recorded, 98 are proven or suspected vectors of human leishmaniases; these include 42 Phlebotomus species in the Old World and 56 Lutzomyia species in the New World (all: Diptera: Psychodidae). Based on incrimination criteria, we provide an updated list of proven or suspected vector species by endemic country where data are available. Increases in sandfly diffusion and density resulting from increases in breeding sites and blood sources, and the interruption of vector control activities contribute to the spreading of leishmaniasis in the settings of human migration, deforestation, urbanization and conflict. In addition, climatic changes can be expected to affect the density and dispersion of sandflies. Phlebovirus infections and diseases are present in large areas of the Old World, especially in the Mediterranean subregion, in which virus diversity has proven to be higher than initially suspected. Vesiculovirus diseases are important to livestock and humans in the southeastern U.S.A. and Latin America, and represent emerging human threats in parts of India. Carrion's disease, formerly restricted to regions of elevated altitude in Peru, Ecuador and Colombia, has shown recent expansion to non-endemic areas of the Amazon basin.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1365-2915.2012.01034.x

Phlebotomine sandflies and the spreading of leishmaniases and other diseases of public health concern

The leishmaniases as emerging and reemerging zoonoses.

The current status of zoonotic leishmaniases and approaches to disease control.

Phlebotomines are the sole or principal vectors of Leishmania, Bartonella bacilliformis, and some arboviruses. The coevolution of sand flies with Leishmania species of mammals and lizards is considered in relation to the landscape epidemiology of leishmaniasis, a neglected tropical disease. Evolutionary hypotheses are unresolved, so a practical phlebotomine classification is proposed to aid biomedical information retrieval. The vectors of Leishmania are tabulated and new criteria for their incrimination are given. Research on fly-parasite-host interactions, fly saliva, and behavioral ecology is reviewed in relation to parasite manipulation of blood feeding, vaccine targets, and pheromones for lures. Much basic research is based on few transmission cycles, so generalizations should be made with caution. Integrated research and control programs have begun, but improved control of leishmaniasis and nuisance-biting requires greater emphasis on population genetics and transmission modeling. Most leishmaniasis transmission is zoonotic, affecting the poor and tourists in rural and natural areas, and therefore control should be compatible with environmental conservation.

Biology of Phlebotomine Sand Flies as Vectors of Disease Agents

Mapping the potential distribution of Phlebotomus martini and P. orientalis (Diptera: Psychodidae), vectors of kala-azar in East Africa by use of geographic information systems.

In a survey of Leishmania infections in phlebotomine sandflies in a highly suspected focus of leishmaniasis in the Awash Valley (northeastern Ethiopia) between January 1994 and August 1997, a total of 3307 females of 11 Phlebotomus species (P. orientalis, P. fantalensis, P. saevus, P. sergenti, P. gemetchi, P. alexandri, P. bergeroti, P. duboscqi, P. arabicus, P. martini, and P. rodhaini) were dissected. Promastigotes were detected in 17 females of three species (11 P. saevus, 4 P. sergenti and 2 P. arabicus). Of these, only two P. saevus (one from Upper Awash and one from Middle Awash) and three P. sergenti (from Upper Awash) positives were successfully isolated in culture and were typed by isoenzyme analysis. Four isolates (two each from P. saevus and P. sergenti) were identified as new zymodemes (Z) of L. tropica and one isolate from P. sergenti was typed as a new zymodeme of L. aethiopica. This is the first finding of natural infections of P. saevus and P. arabicus and the first evidence for the former to be a vector of L. tropica. This is also the first time P. sergenti has been implicated in L. tropica transmission in Ethiopia; the isolation of L. aethiopica from a Paraphlebotomus species (P. sergenti) is also a new record. The possible presence of human cutaneous leishmaniasis (L. tropica and L. aethiopica), and wild reservoir host(s) of the parasites, especially rock hyrax (Procavia capensis) in the Upper and Middle Awash Valley remain to be determined.

The isolation of Leishmania tropica and L. aethiopica from Phlebotomus (Paraphlebotomus) species (Diptera: Psychodidae) in the Awash Valley, northeastern Ethiopia

In a population of some 4600 people in southern Ethiopia, in which visceral leishmaniasis is endemic, 142 cases were recorded in an 8-year period to 1990. The cases were very unequally distributed ...

Visceral leishmaniasis in Ethiopia. IV. Prevalence, incidence and relation of infection to disease in an endemic area.

Objective: To assess the impact of livestock keeping on the human biting rate (HBR) of anopheline mosquitoes and malaria transmission around Ziway in the middle course of the Ethiopian Rift Valley. Design: As a passive experiment, man landing captures were done in homesteads with mixed dwelling, separate cattle shed and without livestock; and as an active experiment, captures were in experimental tukuls (huts) of cattle, goats, and without livestock. Parasite and spleen rates of children were compared among those residents under variable living conditions mentioned for passive experiment. Subjects: For entomological study, human-baits were used for man-landing captures of mosquitoes. Study subjects for parasitological and clinical studies were children below 10 years old. Main outcome measures: Human-biting rate (HBR) of anopheline mosquitoes; and the parasite and spleen rates of the study subjects in different living conditions. Results: In the passive experiment, the mean HBR of Anopheles arabiensis in mixed dwelling, separate cattle shed and without livestock was 8.45, 4.64 and 5.97, respectively. Similarly, the HBR of An. pharoensis was 2.88, 1.79 and 1.61, respectively. In the active experiment, the mean HBR of An. arabiensis in tukuls with cattle, goats, and without livestock was 3.50, 3.38 and 1.43 respectively; while that of An. pharoensis was 0.37, 0.70 and 0.55 respectively. Parasitologically, mean parasite rates of 26.67%, 15.05% and 23.85% were, respectively, recorded from children living under the above conditions stated for passive experiment. Similarly, the mean spleen rates of 50.0%, 26.9%, and 47.37% were recorded, respectively. Conclusion: These observations in the present study indicate that the presence of cattle in homesteads tends to increase the man biting rate of An. arabiensis, although differences in the mean HBR of vector mosquitoes were not statistically significant for all groups. In contrast, cattle keeping in separate cattle sheds outside of the human dwellings tends to reduce the man biting rate of An. arabiensis and malaria transmission in the study area.

/pdf/impact-of-cattle-keeping-on-human-biting-rate-of-anopheline-1idxz6k37p.pdf

Impact of cattle keeping on human biting rate of anopheline mosquitoes and malaria transmission around ziway, ethiopia

A cross-sectional leishmanin skin test was carried out on a sample population of 730 individuals. The overall prevalence of leishmanin positivity was 36·4%; 50·9% of males and 23·2% of females showed positive skin test reaction. The skin-test profile in the study area is typical of an endemic focus of visceral leishmaniasis. The increase in leishmanin positivity with age parallels the age-specific disease profile and indicates an outdoor exposure to infection.

A Ali

Papers

Mapping the potential distribution of Phlebotomus martini and P. orientalis (Diptera: Psychodidae), vectors of kala-azar in East Africa by use of geographic information systems.

The isolation of Leishmania tropica and L. aethiopica from Phlebotomus (Paraphlebotomus) species (Diptera: Psychodidae) in the Awash Valley, northeastern Ethiopia

Visceral leishmaniasis in Ethiopia. IV. Prevalence, incidence and relation of infection to disease in an endemic area.

Impact of cattle keeping on human biting rate of anopheline mosquitoes and malaria transmission around ziway, ethiopia

Visceral leishmaniasis in Ethiopia. I: Cross-sectional leishmanin skin test in an endemic locality