Leishmania amazonensis isolated from human visceral leishmaniasis: histopathological analysis and parasitological burden in different inbred mice.

Leishmania amazonensis is a major etiological agent of human cutaneous leishmaniasis in the Americas; nevertheless there are some reports of this species causing visceral disease in dogs and men. In the present work we have studied a Leishmania strain isolated from a human case of visceral leishmaniasis. We have infected different mouse strains and analyzed the development of the disease, studying the parasite's ability to visceralize and whether this ability is influenced by host genetics. Female BALB/c, C57BL/6, C57BL/10, CBA, DBA/2, and C3H/He mice were subcutaneously infected with 104 L. amazonensis amastigotes. BALB/c, C57BL/6 and C57BL/10 mice were found to be very susceptible to infection, showing lesions that developed to necrosis and ulceration. CBA mice developed a late but severe lesion. DBA/2 mice developed only discrete lesions, while C3H/He mice did not develop any lesions. All mouse strains except C3H/He showed some degree of visceralization, presenting parasites in the spleen, while BALB/c, C57BL/6 and CBA presented parasites also in the liver. Moreover, most of the strains presented high parasite load at the infection site, whereas DBA and C3H/He mice showed low or no parasite load 90 days after infection, respectively. Histopathology corroborates the results, showing that susceptible mice presented an inflammatory reaction with parasites in the skin, lymph nodes and spleen, while strains that are more resistant presented low parasitism and discrete inflammatory reaction. Results indicate that this isolate is extremely virulent, can easily visceralize and that the pathogenesis of leishmaniasis is, at least in part, related to the genetic background of the host.

Eco-epidemiology of visceral leishmaniasis in the urban area of Paracatu, state of Minas Gerais, Brazil.

The present study was developed in the urban area of Paracatu, an endemic city for the American visceral leishmaniasis in Brazil. A six-month canine survey was performed with 6295 domiciled dogs in 28 districts in that area and showed that 4.2% of those (267 dogs) were positive for VL by ELISA and IFAT serum assays. Prevalence ratios for canine VL varied between 1.2% and 16.1%, depending on the district under investigation. Fifteen dogs - 80% of which were clinically asymptomatic for VL - were submitted to a more detailed study that comprised direct parasitological examination and Leishmania kDNA amplification of tissue samples as well as two PCR-RFLP methods using myelocultures. Leishmania amastigotes or Leishmania DNA were detected in all dogs but one. The infecting species of Leishmania was identified in about 50% (7/15) of the sample dogs: Leishmania (Leishmania) chagasi in two of them and, unexpectedly, Leishmania (Leishmania) amazonensis in the remaining five. Three months after the end of confiscation and elimination of the VL-seropositive dogs in the 28 districts of Paracatu, a systematic entomological survey was performed in five of them. Six hundred and sixty five (665) phlebotomine sand flies were captured in total, from which 89.5% were identified as Lutzomyia longipalpis. The population density of that species increased during the rainy season. Other thirteen (13) species of phlebotomine sand flies were captured at varying percentages from 0.2 to 5.0%. It is worth noting that L. longipalpis females were predominantely intradomicile when compared to males, suggesting that the VL transmission cycle in Paracatu may be occurring inside home.

Infectivity of seropositive dogs, showing different clinical forms of leishmaniasis, to Lutzomyia longipalpis phlebotomine sand flies.

Visceral leishmaniasis (VL) is a growing zoonosis with an increasing number of new cases and a rapid geographical spreading of the disease. In the present study, a canine survey was carried out in the city of Montes Claros (320,000 inhabitants), an endemic area of American visceral leishmaniasis in the state of Minas Gerais, Brazil. A total number of 4795 dogs were examined by serology, which showed a rate of seropositivity of 5%. Isoenzymatic analysis confirmed Leishmania infantum chagasi as the local aetiological agent of CVL. Canine tissues were assayed for the presence of Leishmania parasite DNA using different techniques. The infectivity of asymptomatic, oligosymptomatic and symptomatic seropositive dogs was tested by xenodiagnosis using laboratory reared Lutzomyia longipalpis. Rates of infection of 5.4%, 5.1% and 28.4% were found for the phlebotomine sand flies that fed in asymptomatic, oligosymptomatic and symptomatic dogs, respectively. Our results indicate that, under experimental conditions, symptomatic dogs are about four times more infective to VL vectors than oligosymptomatic or asymptomatic animals. The lower infectivity rates of dogs displaying any of the last two clinical forms of leishmaniasis, however, must be taken into account in the epidemiology of CVL.

Visceral leishmaniasis caused by Leishmania (Viannia) braziliensis in a patient infected with human immunodeficiency virus.

The current article reports the case of a 19-month-old-girl, from the state of Minas Gerais, Brazil, with visceral leishmaniasis, by Leishmania (Viannia) braziliensis, and Human Immunodeficiency Virus (HIV) co-infection. The child's mother and father, aged 22 and 27 years old, respectively, were both HIV positive. The child was admitted to the General Pediatric Center, in Belo Horizonte, presenting high fever, fatigue, weight loss and enlargement of liver and spleen. Indirect immunofluorescent test revealed a titer of 1:320 for Leishmania. Such result was confirmed by the presence of amastigotes in bone marrow aspirate samples and culture of promastigote forms. Parasites were identified as being Leishmania (Viannia) braziliensis through PCR, using a L. braziliensis complex primer and a generic primer, followed by hibridization. Specific leishmaniasis therapy (Glucantime register mark or target antimonial) was intravenously administered.

Visceral leishmaniasis caused by Leishmania (Viannia) braziliensis in a patient infected with human immunodeficiency virus

The current article reports the case of a 19-month-old-girl, from the state of Minas Gerais, Brazil, with visceral leishmaniasis, by Leishmania (Viannia) braziliensis, and Human Immunodeficiency Virus (HIV) co-infection. The child's mother and father, aged 22 and 27 years old, respectively, were both HIV positive. The child was admitted to the General Pediatric Center, in Belo Horizonte, presenting high fever, fatigue, weight loss and enlargement of liver and spleen. Indirect immunofluorescent test revealed a titer of 1:320 for Leishmania. Such result was confirmed by the presence of amastigotes in bone marrow aspirate samples and culture of promastigote forms. Parasites were identified as being Leishmania (Viannia) braziliensis through PCR, using a L. braziliensis complex primer and a generic primer, followed by hibridization. Specific leishmaniasis therapy (Glucantimeomicron antimonial) was intravenously administered