Maria do Carmo Custódio de Souza Hunold Lara

Bat rabies in the north-northwestern regions of the state of São Paulo, Brazil: 1997-2002

OBJECTIVE Reports on bat rabies in Brazil are sporadic and isolated. This study aimed at describing the detection of rabies virus in bats in the state of São Paulo. METHODS A total of 7,393 bats from 235 municipalities of the north and northwestern areas of the state of São Paulo, Southeastern Brazil, were assessed according to their morphological and morphometric characteristics from 1997 to 2002. Fluorescent antibody test and mice inoculation were used for viral identification. RESULTS Of all samples examined, 1.3% was rabies virus positive, ranging from 0.2% in 1997 to 1.6% in 2001. There were found 98 bats infected, 87 in the urban area. Fluorescent antibody test was detected in 77 positive samples, whereas 92 produced rabies signs in mice; incubation period ranging from 4 to 23 days. In 43 cities at least one rabid bat was observed. The highest proportion (33.7%) of rabies virus was found in Artibeus lituratus. Eptesicus and Myotis were the most frequent positive species (24.5%) of the Vespertilionidae family. The species Molossus molossus and Molossus rufus showed 14.3% positive bats. There were no differences in the distribution of positive rabies between females (33; 48.5%) and males (35; 51.5%). CONCLUSIONS Rabies-infected bats were found in environments that pose a risk to both human and domestic animal population and there is a need for actions aiming at the control of these species and public education.

West Nile virus surveillance, Brazil, 2008-2010

BACKGROUND West Nile virus (WNV) is an emergent pathogen that is widely distributed in North and Central America. The recent introduction in South America has focused attention on the spread of WNV across Southern American countries. The transmission network involves mosquitoes, birds, horses and humans. METHODS The serological evaluation of sera from 678 equids and 478 birds was performed using a WNV-specific blocking ELISA, and only the positive results were confirmed by plaque reduction neutralisation tests (PRNTs). Molecular analysis was performed on sera from 992 healthy equids and on 63 macerates of brains from equids that died of encephalitis and had previously tested negative for other pathogens. We also tested swabs from 928 birds. The samples analysed were collected in different biomes of Brazil. RESULTS We identified WNV antibodies by ELISA in thirteen equids and five birds, and PRNT90 confirmed WNV positivity in four equid samples collected in 2009 in an area between the Amazon and the Pantanal. None of the ELISA positive bird samples were confirmed by PRNT90, and all samples tested by RT-PCR were negative. CONCLUSION WNV circulation is confirmed by this large scale survey even in the absence of detection of clinical cases.

Equid herpesvirus type-1 exhibits neurotropism and neurovirulence in a mouse model.

Intranasal inoculation of equid herpesvirus type-1 (EHV-1) Brazilian strains A4/72 and A9/92 induced an acute and lethal infection in four different inbred mouse strains. Clinical and neurological signs appeared between the 2nd and 3rd day post inoculation (dpi) and included weight loss, ruffled fur, a hunched posture, crouching in corners, nasal and ocular discharges, dyspnoea, dehydration and increased salivation. These signs were followed by increased reactivity to external stimulation, seizures, recumbency and death. The virus was recovered consistently from the brain and viscera of all mice with neurological signs. Histopathological changes consisted of leptomeningitis, focal haemorrhage, ventriculitis, neuronal degeneration and necrosis, neuronophagia, non-suppurative inflammation, multifocal gliosis and perivascular infiltration of polymorphonuclear and mononuclear cells. Immunohistochemical examination demonstrated that EHV-1 strains A4/72 and A9/92 replicated in neurons of the olfactory bulb, the cortex and the hippocampus. In contrast, mice inoculated with the EHV-1 Brazilian strain A3/97 showed neither weight loss nor apparent clinical or neurological signs; however, the virus was recovered consistently from their lungs at 3 dpi. These three EHV-1 strains showed distinct degrees of virulence and tissue tropism in mice. EHV-1 strains A4/72 and A9/92 exhibited a high degree of central nervous system tropism with neuroinvasion and neurovirulence. EHV-1 strain A3/97 was not neurovirulent despite being detected in the brains of infected BALB/c nude mice. These findings indicate that several inbred mouse strains are susceptible to neuropathogenic EHV-1 strains and should be useful models for studying the pathogenesis and mechanisms contributing to EHV-induced myeloencephalopathy in horses.

Pathogenicity of different rabies virus isolates and protection test in vaccinated mice

This study was aimed to evaluate and compare the pathogenicity of rabies virus isolated from bats and dogs, and to verify the efficacy of a commercial rabies vaccine against these isolates. For evaluation of pathogenicity, mice were inoculated by the intramuscular route (IM) with 500MICLD₅₀/0.03 mL of the viruses. The cross-protection test was performed by vaccinating groups of mice by the subcutaneous route and challenged through the intracerebral (IC) route. Isolates were fully pathogenic when inoculated by the IC route. When inoculated intramuscularly, the pathogenicity observed showed different death rates: 60.0% for the Desmodus rotundus isolate; 50.0% for dog and Nyctinomops laticaudatus isolates; 40.0% for Artibeus lituratus isolate; 9.5% Molossus molossus isolate; and 5.2% for the Eptesicus furinalis isolate. Mice receiving two doses of the vaccine and challenged by the IC route with the isolates were fully protected. Mice receiving only one dose of vaccine were partially protected against the dog isolate. The isolates from bats were pathogenic by the IC route in mice. However, when inoculated through the intramuscular route, the same isolates were found with different degrees of pathogenicity. The results of this work suggest that a commercial vaccine protects mice from infection with bat rabies virus isolates, in addition to a canine rabies virus isolate.

Aspectos clínicos da artrite-encefalite dos caprinos

In a clinical survey of caprine arthritis-encephalitis in 14 naturally infected herds in the State of Sao Paulo, Brazil, 17.1% (64/374) of seroreagents presented the articular form of the disease and 6.6% (17/249) of the seroreagent females presented the mammary form of the disease.

Detection of Neospora sp. antibodies in cart horses from urban areas of Curitiba, Southern Brazil

Neospora caninum is a protozoan parasite which affects dogs as definitive hosts and several mammalian species as intermediate hosts mainly causing abortions and central nervous system disorders. The reemerging population of cart horses for carrying recycling material in urban areas of major cities in Brazil may have an impact on disease spreading, and these animals may be used as sentinels for environmental surveillance. Thus, the present study investigated the frequency of Neospora sp. antibodies in cart horses from Curitiba and surrounding areas, Paraná State, Southern Brazil. IgG antibodies against Neospora sp. were detected using indirect fluorescence antibody test (IFAT), and titers equal to or higher than 1:50 were considered reactive. Of all samples, 14/97 (14.4%) were positive: 2/29 (6.9%) were younger than 5; 5/26 (19.2%) between 6 and 9; and 6/31 (19.4%) older than 10 years of age. One of the 11 animals with unknown age was positive (9.1%). Cart horses are likely to be more exposed to dog feces and to Neospora sp. oocyst contamination in urban settings and a lower frequency of disease in dogs may have a negative impact on horse infection risk in these areas.

Antibodies against pseudorabies virus in feral swine in southeast Brazil

Soros de 358 javalis (Sus scrofa), criados em sistema de semiconfinamento em propriedades do estado de Sao Paulo, foram coletados entre 1998 e 2000 e testados para anticorpos contra o virus da doenca de Aujeszky (VDA), pela tecnica de soroneutralizacao (SN) e ensaio imunoenzimatico (ELISA). Foram detectados animais soropositivos em tres das sete propriedades analisadas. Do total de javalis testados, 30,7% apresentaram anticorpos neutralizantes contra o VDA, com variacao de 25,2% a 100% nas propriedades com animais sororreagentes. O ELISA detectou menor numero de sororeagentes (19,3%), sendo a sensibilidade e a especificidade 57,3% e 97,6%, respectivamente, e a correlacao observada de 85,2% (P<0,0001). Os resultados mostram que a infeccao pelo virus da doenca de Aujeszky ocorre em criacoes de javalis no estado de Sao Paulo, e compromete o sucesso de um futuro programa de erradicacao da doenca na regiao.

Detection of anti-Toxoplasma gondii antibodies in carthorses in the metropolitan region of Curitiba, Paraná, Brazil.

Toxoplasma gondii, the agent for toxoplasmosis, has worldwide distribution. Horses normally play a secondary role in its life cycle, but movement around urban areas, feeding on grass and the increasing use of carthorses for gathering recyclable material in some urban areas of Brazil may increase their exposure to T. gondii infection. The aim of the present study was to investigate the frequency of anti-T. gondii antibodies in carthorses in the metropolitan region of Curitiba, PR. IgG antibodies against T. gondii were detected using the indirect fluorescence antibody test (IFAT) (titers ≥ 64). Seventeen (17.0%) of the 100 horses sampled were seropositive. There were no statistical differences in relation to sex (p = 0.28) or age (p = 0.15). Our findings suggest that carthorses are exposed to T. gondii infections and that no associations with age or sex exist.

Isolamento do vírus da raiva em Artibeus fimbriatus no Estado de São Paulo

This is the first report of the isolation and identification of the rabies virus in the frugivorous bat Artibeus fimbriatus in the city of Sao José do Rio Preto, Sao Paulo State, Brazil. The virus was isolated from an animal found in an urban area. The animal was found on the ground under a tree, still alive. Diagnosis was made by direct immunofluorescence and intracerebral inoculation of mice.

Prevalência de anticorpos antivírus da arterite dos eqüinos em cavalos criados no Estado de São Paulo

With the purpose of studying the prevalence of equine viral arteritis in horses raised in Sao Paulo State, Brazil, by the standard microtiter serum neutralization test, 659 serum samples were investigated. The prevalence of antibodies in the horse population was 18.2%, which was significantly higher in Mangalarga horses (33.3%) than in any other breed (Thoroughbred, Arab, Quarter Horse, mixed breeds and others). The distribuition of horses by age showed that horses between 6 to 24 months of age (30.4%) had a higher prevalence (30.4%) rate than others. The female horses prevalence rate of 22.9% was significantly higher than in male horses.