Relationship between dog culling and incidence of human visceral leishmaniasis in an endemic area

Domestic dogs are the main reservoirs of visceral leishmaniasis (VL) in urban areas; one of the control measures adopted in Brazil is the elimination of this reservoir. In order to test the relationship between the euthanasia rate of the canine reservoir and the incidence of the disease in humans, data on dog culling from the Centre for Zoonosis Control of Aracatuba, São Paulo, Brazil, during the period from 1999 to 2008 and visceral leishmaniasis human cases registered in the same period were analyzed. Reduction of human VL incidence was statistically correlated to dog euthanasia rate (P=0.0211; r(2)=0.616) when it was analyzed for the period of two years after application of this measure. Other factors that may influence this relationship are considered. (C) 2010 Elsevier B.V. All rights reserved.

Development of the inverted visceral yolk sac in three species of caviids (rodentia, caviomorpha, caviidae)

Guinea pig related rodents possess numerous derived placental characters. We attempt to identify diversity within the visceral yolk sac and its association with the chorioallantoic placenta in three species of caviids, two of them possessing a capsule formed by the decidua that covers the chorioallantoic placenta. The results verify that in early pregnancy all three species have in inverted yolk sac placenta. In advanced pregnancy the species differ: Galea spixii, as representative without a capsule, bear a yolk sac in apposition to the chorioallantoic placenta with signs of exchange activity until term. Galea is similar to other caviomorphs in this respect. In Dasyprocta leporina and Cuniculus paca, the representatives possessing a capsule, the yolk sac endoderm lacks signs of substance exchange. Evidently, the presence of a capsule prevents such ail interaction. The variations established here must be considered if animal models for human placentation are required which have restricted access to the chorioallantoic placenta from the outside. (C) 2008 Elsevier Ltd. All rights reserved.

Dog culling and replacement in an area endemic for visceral leishmaniasis in Brazil

Measures employed to control visceral leishmaniasis in Brazil have focused on vector control by residual insecticide spraying and diagnosis of infection with elimination of positive dogs. We describe dog culling and replacement in a Brazilian endemic area (the Alvorada District, Aracatuba, SP) in order to better understand dog population dynamics when elimination of the dog reservoir is adopted as the main control measure. From August 2002 to July 2004, 60.9% of the estimated dog population for the area was culled with a mean age of 34 months old. The presence of anti-Leishmania sp. antibodies was recorded for only 26.7% of the euthanized canines. Replacement was observed in 38.8% of the cases, some of them by 2 or more dogs and in a mean time of 4 months. Dogs were replaced mostly by puppies of both sexes with a mean age of 6.8 months. From August 2002 to April 2005 we were able to follow-up 116 of these dogs, during a mean time of 8.7 months. Canine visceral leishmaniasis seropositivity by ELISA was observed in 42.2% of the followed dogs, 30.6% of which were already positive at the first evaluation. By the end of the follow-up period 37% of the dogs were submitted to euthanasia, with a mean age of 18.3 months. In the studied CVL endemic area of Brazil, euthanasia and the subsequent replacement ratio were high, increasing the dog population turnover and leading to a younger population that might be more susceptible to a variety of other infectious diseases in addition to CVL. Dog culling as a control strategy for VL should be reassessed. (C) 2008 Elsevier B.V. All rights reserved.

Potential role for dog fleas in the cycle of Leishmania spp.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

IgG subclass profile of serum antibodies to Leishmania chagasi in naturally infected and vaccinated dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caso alóctone de leishmaniose visceral canina, no município de Campo Mourão, Paraná, Brasil

This report aims to describe the first case allochthonous of visceral leishmanisasis (VL) in the municipality of Campo Mourao, Parana, Brazil, in a canine, Boxer breed, with eye and skin lesions, lymphadenomegaly and splenomegaly, attended at Veterinary Hospital at the Faculdade Integrado de Campo Mourao, after residing in the city of Campo Grande, Mato Grosso do Sul. The diagnosis of the disease was based on direct observation of amastigotes of Leishmania spp., in popliteal lymph nodes, suggesting that a case of VL, since the animal came from an endemic area for the disease. The migration of infected dogs from endemic regions to areas unaffected becomes a problem for public health, since it may allow the installation of new outbreaks by encouraging the spread of disease throughout the country.

Cross-reactions between Toxocara canis and Ascaris suum in the diagnosis of visceral larva migrans by western blotting technique

Visceral larva migrans (VLM) is a clinical syndrome caused by infection of man by Toxocara spp, the common roundworm of dogs and cats. Tissue migration of larval stages causes illness specially in children. Because larvae are difficult to detect in tissues, diagnosis is mostly based on serology. After the introduction of the enzyme-linked immunosorbent assay (ELISA) using the larval excretory-secretory antigen of T. canis (TES), the diagnosis specificity was greatly improved although cross-reactivity with other helminths are still being reported. In Brazil, diagnosis is routinely made after absorption of serum samples with Ascaris suum antigens, a nematode antigenicaly related with Ascaris lumbricoides which is a common intestinal nematode of children. In order to identify T. canis antigens that cross react to A. suum antigens we analyzed TES antigen by SDS-PAGE and Western blotting techniques. When we used serum samples from patients suspected of VLM and positive result by ELISA as well as a reference serum sample numerous bands were seen (molecular weight of 210-200 kDa, 116-97 kDa, 55-50 kDa and 35-29 kDa). Among these there is at least one band with molecular weight around 55-66 kDa that seem to be responsible for the cross-reactivity between T. canis and A. suum once it disappears when previous absorption of serum samples with A. suum antigens is performed.