BACKGROUND Non-human primates contribute to the spread of the yellow fever virus (YFV) and the establishment of transmission cycles in endemic areas. OBJECTIVE To describe the severe histopathological aspects of YFV infection, 10 squirrel monkeys were infected with YFV and blood, brain, liver, kidney, spleen, heart, lung, lymph node and stomach were collected at 1-7, 10, 20 and 30 days post-infection (dpi). METHODS Histopathological analysis and detection of the genome and viral antigens and neutralising antibodies were performed by RT-PCR, immunohistochemistry and neutralisation test, respectively. FINDINGS Only one animal died from the experimental infection. The genome and viral antigens were detected in all investigated organs (1-30 dpi) and the neutralising antibodies from seven to 30 dpi. The brain contained perivascular haemorrhage (6 dpi); in the liver, midzonal haemorrhage and lytic necrosis (6 dpi) were observed. The kidney had bleeding in the Bowman’s capsule and tubular necrosis (6 dpi). Pyknotic lymphocytes were observed in the spleen (1-20 dpi), the lung had haemorrhage (2-6 dpi), in the endocardium it contained nuclear pyknosis and necrosis (2-3 dpi) and the stomach contained blood in the lumen (6 dpi). MAIN FINDINGS Squirrel monkeys reliably reproduced the responses observed in human cases of yellow fever and, therefore, constitute an excellent experimental model for studies on the pathophysiology of the disease.

São descritos os achados clínico-laboratoriais da infecção acidental pelo virus SP H 114202 (Arenavirus, família Arenaviridae), um virus novo causador de febre hemorrágica humana. O paciente, técnico de laboratório, apresentou quadro febril por 13 dias. A doença cursou com febre elevada ( 39ºC.) diária, cefaléia, calefrios e mialgias por 8 dias. A partir do 3º dia surgiram náuseas, vômitos alimentares e anorexia e no 10º dia, epigastralgia, diarréia e gengivorragia. Laboratorialmente, foram observadas as seguintes alterações: leucopenia gradativa com linfocitose a medida que a doença evoluía, passando de 5800 para 4100, 3400 e 2500 leucócitos por mm³ de sangue com 2,5,9 e 11 dias de doença, respectivamente. Ocorreram ainda, discretas alterações nas transaminases (TGO=54 e TGP=52) no 9º dia de doença. O coagulograma e velocidade de hemossedimentação foram normais. Conversão sorológica para o virus em apreço, foi detectada através dos testes de fixação do complemento, neutralização e ELISA. Sangue do paciente inoculado em camundongos recém nascidos, hamsters e células VERO, apresentou resultado negativo para isolamento de virus. Esse virus foi isolado pela primeira vez em São Paulo, em 1990, a partir do sangue de um paciente que apresentou febre hemorrágica com evolução fatal. Recomenda-se extremo cuidado no manuseio desse virus por tratar-se de patógeno com riscos de transmissão por aerossóis (contaminante classe III ou IV).

Here in is described the clinical and laboratorial findings of a laboratory-acquired infection caused by the virus SP H 114202 (Arenavirus, family Arenaviridae) a recently discovered agent responsible for a viral hemorrhagic fever. The patient was sick for 13 days. The disease had an abrupt onset characterized by high fever (39ºC.), headache, chills and myalgias for 8 days. In addition, on the 3rd day, the patient developed nauseas and vomiting, and in the 10th, epigastralgia, diarrheia and gengivorrhagia. Leucopenia was seen within the 1 st week of onset, with counts as low as 2,500 white cells per mm³. Counts performed after the 23th day of the onset were within normal limits. With the exception of moderate lymphocitosis, no changes were observed in differential counts. An increase in the liter of antibodies by complement fixation, neutralization and ELISA (IgM) was detected. Suckling mice and baby hamsters were inoculated intracerebrally with 0.02 ml of blood samples collected in the 2nd and 7th days of disease. Attempts to isolate the virus were also made in Vero cells. No virus was isolated. This virus was isolated before in a single occasion in São Paulo State, in 1990, from the blood of a patient with hemorrhagic fever with a fatal outcome. The manipulation of the virus under study, must be done carefully, since the transmission can occur through aerosols.

The phlebotomine sand fly fauna of two coffee plantations in a Leishmania-endemic area of Norte de Santander, Colombia was studied. Regular insect collections using a variety of methods were made for three and a half years. Information was obtained on diurnal resting sites, host range and seasonal abundance for 17 species, of wich five (Lutzomyia spinicrassa, Lu. serrana,Lu. shannoni, Lu. ovallesi and Lu. gomezi) were far more numerous than the others, anthropophilic and present throughout the year. The behaviour of these and the remaining 12 species is discussed in relation to their potential role in transmission of Leishmania (Viannia) brasiliensis in the area.

Characterization is given of a new parasite, Leishmania equatoriensis sp.n. wich was isolated from the viscera of a sloth (Choloepus hoffmanni) and a squirrel (Sciurus granatensis), captured in humid tropical forest onthe Pacific Coast of Ecuador. Data based on biological and molecular criteria, as well as numerical zymotaxonomical analysis, indicate that this parasite is a new species of the L. brasiliensis complex. L. equatoriensis is cleary distinguishable form all other known species within this complex, using the following molecular criteria: reactivity patterns with specific monoclonal antibodies, isoenzyme electrophoresis, and restriction-endonuclease fragment patterns of kinetoplast DNA (k-DNA).