Silvana Regina Favoretto

Antigenic typing of brazilian rabies virus samples isolated from animals and humans, 1989-2000

Animal and human rabies samples isolated between 1989 and 2000 were typified by means of a monoclonal antibody panel against the viral nucleoprotein. The panel had been previously established to study the molecular epidemiology of rabies virus in the Americas. Samples were isolated in the Diagnostic Laboratory of the Pasteur Institute and in other rabies diagnostic centers in Brazil. In addition to the fixed virus samples CVS-31/96-IP, preserved in mouse brain, and PV-BHK/97, preserved in cell culture, a total of 330 rabies virus samples were isolated from dogs, cats, cattle, horses, bats, sheep, goat, swine, foxes, marmosets, coati and humans. Six antigenic variants that were compatible with the pre-established monoclonal antibodies panel were defined: numbers 2 (dog), 3 (Desmodus rotundus), 4 (Tadarida brasiliensis), 5 (vampire bat from Venezuela), 6 (Lasiurus cinereus) and Lab (reacted to all used antibodies). Six unknown profiles, not compatible with the panel, were also found. Samples isolated from insectivore bats showed the greatest variability and the most commonly isolated variant was variant-3 (Desmodus rotundus). These findings may be related to the existence of multiple independent transmission cycles, involving different bat species.

Prolonged Shedding of Zika Virus Associated with Congenital Infection

In this case report, Zika virus was detected in the bloodstream of an infant who was congenitally infected for at least 2 months after birth.

Simplified fluorescent inhibition microtest for the titration of rabies neutralizing antibodies

A simplified fluorescence inhibition microtest (SFIMT) was standardized for the evaluation of antirabies serum neutralizing antibodies based on the rapid fluorescent focus inhibition test (RFFIT) and the fluorescence inhibition microtest (FIMT). The simplified test showed reproducibility similar to that of the FIMT with advantages as easier executation and quicker reading. A simple pre-treatment of Brazilian microplates produced for immune enzymatic assays (PROSIL) gave equivalent results and substantial coast reduction, in relation to imported plates (DIFCO). The simplified test can be easily implemented in less sophisticated laboratories, as alternative to the mouse serum neutralization test, still the most largely employed in Brazil, or even to others as RFFIT and FIMT.

Rabies Virus Maintained by Dogs in Humans and Terrestrial Wildlife, Ceará State, Brazil

Rabies viruses circulating in Ceará, Brazil, were identified by molecular analysis to be related to variants maintained by dogs, bats, and other wildlife. Most of these viruses are associated with human rabies cases. We document the emergence of a rabies virus variant responsible for an independent epidemic cycle in the crab-eating fox (Cerdocyon thous).

Antigen profile of rabies virus isolated from different species of non-hematophagous bats in the region of Presidente Prudente, State of São Paulo

Using the monoclonal antibody technique, the Clinical and Molecular Virology Laboratory of the Institute of Biomedical Sciences of the University of São Paulo typed 18 rabies virus samples from non-hematophagous bats of several species from the region of Presidente Prudente, SP, Brazil. Among these samples, 15 (82.3%) were defined as variant 3 (compatible with samples isolated from Desmodus rotundus bats) and three (16.7%) as variant 4 (compatible with samples isolated from Tadarida brasiliensis bats).

Rabies in southeast Brazil: a change in the epidemiological pattern

This epidemiological study was conducted using antigenic and genetic characterisation of rabies virus isolates obtained from different animal species in the southeast of Brazil from 1993 to 2007. An alteration in the epidemiological profile was observed. One hundred two samples were tested using a panel of eight monoclonal antibodies, and 94 were genetically characterised by sequencing the nucleoprotein gene. From 1993 to 1997, antigenic variant 2 (AgV-2), related to a rabies virus maintained in dog populations, was responsible for rabies cases in dogs, cats, cattle and horses. Antigenic variant 3 (AgV-3), associated with Desmodus rotundus, was detected in a few cattle samples from rural areas. From 1998 to 2007, rabies virus was detected in bats and urban pets, and four distinct variants were identified. A nucleotide similarity analysis resulted in two primary groups comprising the dog and bat antigenic variants and showing the distinct endemic cycles maintained in the different animal species in this region.

The emergence of wildlife species as a source of human rabies infection in Brazil.

Forty-five human rabies virus isolates from a wide geographical area of Brazil were characterized using an anti-nucleoprotein monoclonal antibody panel and by partial nucleotide sequencing analysis of the nucleoprotein gene. Three major antigenic groups related to the antigenic variants maintained in domestic dogs, vampire bats and marmosets were identified. Phylogenetic analyses revealed that the viruses from dog-related cases segregated into four sister clades: three associated with dog-endemic cycles in Brazil and one with the crab-eating fox cycle in the northeastern region of the country. The vampire bat- and marmoset-related viruses formed two independent groups. The topology of these clades was conserved when these samples were compared to virus representatives of the currently reported rabies endemic cycles in the Americas. These results indicated the presence of multiple endemic transmission cycles maintained in four different reservoirs, domestic dogs, crab-eating foxes, vampire bats and marmosets, which are being transmitted directly to humans and should be considered as a high-risk for rabies infection.

One-step protocol for amplification of near full-length cDNA of the rabies virus genome

Full-length genome sequencing of the rabies virus is not a routine laboratory procedure. To understand fully the epidemiology, genetic variation and evolution of the rabies virus, full-length viral genomes need to be obtained. For rabies virus studies, cDNA synthesis is usually performed using nonspecific oligonucleotides followed by cloning. When specific primers are used, the cDNA obtained is only partial and is limited to the coding regions. Therefore, the development of methods for synthesizing long cDNA using rabies virus-specific primers is of fundamental importance. A new protocol for the synthesis of long cDNA and the development of 19 new primers are described in this study. This procedure allowed the efficient amplification of the full-length genome of the rabies virus variant maintained by hematophagous bat (Desmodus rotundus) populations following the synthesis of a complete long cDNA. Partial sequencing of the rabies virus genome was performed to confirm rabies-specific PCR amplification. Because degenerate primers were employed, this technique can be adapted easily to other variants. Importantly, this new method is faster and less expensive than cloning methods.

Os morcegos e a raiva na região oeste do Estado de São Paulo

INTRODUCTION: The Polo da Alta Sorocabana Laboratory in Presidente Prudente, SP, in partnership with other research institutions, conducted studies related to bats from the western region of the State of Sao Paulo, Brazil. Thus, certain situations were investigated, including: a) isolation of the rabies virus from 2006 to 2008; b) identification of respective antigenic variants; and c) characterization of daytime shelters of Desmodus rotundus vampire bats. METHODS: Samples for examination originated from nonhematophagous bats forwarded to the laboratory and subjected to direct fluorescent antibody test and mouse inoculation test. Positive samples were characterized by the monoclonal antibody test. Regarding the bats, they were identified and classified and mapping of their shelters was also performed. RESULTS: The laboratory received 1,113 nonhematophagous bats for rabies diagnosis, 11 (1%) of which were positives, and among the positive samples, 5 (45.5%) presented antigenic variant 3 (from the bat Desmodus rotundus) and 4 (36.5%) were compatible with samples derived from Brazilian insectivorous bats. Sixteen vampire bat shelters were investigated and observation confirmed the presence of another 3 species of nonhematophagous bats coexisting with them. CONCLUSIONS: The experiments showed that at least 3 antigenic variants of rabies virus are circulating in the region and that the cohabitation of vampire bats with nonhematophagous bats could be related to the dissemination of the rabies virus.

Characterization of rabies virus isolated from a colony of Eptesicus furinalis bats in Brazil

Some bat species have adapted to the expanding human population by acquiring the ability to roost in urban buildings, increasing the exposure risk for people and domestic animals, and consequently, the likelihood of transmitting rabies. Three dead bats were found in the yard of a house in an urban area of Jundiaí city in the state of São Paulo in southeast Brazil. Two of the three bats tested positive for rabies, using Fluorescent Antibody and Mouse Inoculation techniques. A large colony of Eptesicus furinalis was found in the houses attic, and of the 119 bats captured, four more tested positive for rabies. The objectives of this study were to report the rabies diagnosis, characterize the isolated virus antigenically and genetically, and study the epidemiology of the colony.