João Marcelo Azevedo de Paula Antunes

Investigation of tick vectors of Hepatozoon canis in Brazil.

Hepatozoon canis is a common apicomplexan parasite of dogs. In Brazil, in addition to Rhipicephalus sanguineus, Amblyomma ovale, Amblyomma cajennense, and Rhipicephalus (Boophilus) microplus have been suggested to act as vectors. The present study aimed to evaluate, under controlled conditions, the acquisition of H. canis by A. ovale, R. sanguineus, and A. cajennense after feeding on naturally infected dogs. Cytological and histophatological examinations were performed to recover oocysts and other sporogonic stages of the protozoan from the experimentally infected nymphs and adults. None of the R. sanguineus (n=30) or A. cajennense nymphs (n=15) that were dissected after feeding on H. canis naturally infected dogs became infected by the hemoparasite. Likewise, none of the R. sanguineus (n=165) and A. cajennense (n=114) adult ticks that were fed as nymphs on dogs demonstrated infection. Additionally, A. cajennense adult ticks were incapable of acquiring the infection, since no parasite was found in 62 adults that fed on H. canis-infected dogs. With regard to A. ovale ticks, 2 different infestations were carried out. Firstly, a dog with naturally occurring hepatozoonosis was infested with A. ovale adults originating from Rondônia, Brazil. Ticks fed to full engorgement. A total of 31 adults was collected from the dog and dissected on the third day after natural detachment. Oocysts were detected in 13 (42%) of the ticks. The second experimental infestation was carried out using adult ticks originating from São Paulo, Brazil. Surprisingly, of the 103 dissected ticks, only one (1%) contained oocysts in the hemocoel. No other sporogonic stage was found. Results indicate that different strains of A. ovale ticks may exist in Brazil with different susceptibilities to pathogens. Furthermore, it is possible that R. sanguineus and A. cajennense have little or no importance in the transmission of H. canis in rural areas of Brazil.

Vaccinia Virus Zoonotic Infection, São Paulo State, Brazil

To the Editor: Since 1999, vaccinia virus (VACV) has been isolated frequently from dairy cattle and humans (1–3). During bovine vaccinia outbreaks, VACV can be transmitted to farmers and those who milk cows; it frequently causes lesions on the hands and forearms. Bovine vaccinia causes economic losses and affects public health services in Brazil (1–4). One of the first VACV viruses isolated during Brazilian bovine vaccinia outbreaks was Aracatuba virus (ARAV), which was collected in Sao Paulo State, and since that time, other VACVs have been isolated in this state (2,5,6).

Serological study of vaccinia virus reservoirs in areas with and without official reports of outbreaks in cattle and humans in São Paulo, Brazil

Vaccinia virus (VACV), the etiological agent of an exanthematic disease, has been associated with several bovine outbreaks in Brazil since the end of the global vaccination campaign against smallpox. It was previously believed that the vaccine virus used for the WHO global campaign had adapted to an unknown wild reservoir and was sporadically re-emerging in outbreaks in cattle and milkers. At present, it is known that Brazilian VACV is phylogenetically different from the vaccinia virus vaccinal strain, but its origin remains unknown. This study assessed the seroprevalence of orthopoxviruses in domestic and wild animals and farmers from 47 farms in three cities in the southwest region of the state of São Paulo with or without official reports of outbreaks in cattle or humans. Our data indicate a low seroprevalence of antibodies in wild animals and raise interesting questions about the real potential of wild rodents and marsupials as VACV reservoirs, suggesting other routes through which VACV can be spread.

First Identification of Canine Distemper Virus in Hoary Fox (Lycalopex vetulus): Pathologic Aspects and Virus Phylogeny

Canine distemper virus (CDV) has been reported in several wild animal species, but there have been no reports of CDV in hoary fox (Lycalopex vetulus). This paper characterizes the first case of natural CDV infection in hoary fox, including the clinical and pathologic aspects of the disease as well as the viral strain phylogeny.

Saúde gengival de adolescentes e a utilização de serviços odontológicos, Estado de São Paulo = Gingival health of adolescents and the utilization of dental services, state of São Paulo, Brazil

OBJETIVO: Avaliar a associacao de condicoes de saude gengival com a utilizacao de servico odontologico. METODOS: Realizou-se levantamento epidemiologico de saude bucal de 1.799 adolescentes, em 35 cidades do Estado de Sao Paulo, em 2002. A saude gengival foi avaliada pela prevalencia de sangramento na gengiva a sondagem e calculo dentario (indice periodontal comunitario) e oclusao dentaria (indice de estetica dentaria). A utilizacao de servicos odontologicos foi medida pelo indice de cuidado (O/CPO) para cada cidade. Analise multinivel de regressao logistica ajustou modelos explicativos para fatores associados aos desfechos de interesse. RESULTADOS: A prevalencia de sangramento gengival a sondagem foi 21,5%; de calculo dentario foi 19,4%. Os participantes do sexo masculino, negros e pardos, moradores em areas rurais, residentes em domicilios aglomerados e com atraso escolar apresentaram chance significantemente mais elevada para os agravos que seus respectivos pares de comparacao. Caracteristicas de oclusao dentaria tambem associaram com gengiva nao-saudavel: apinhamento dos segmentos incisais, mordida aberta vertical anterior, relacao molar antero-posterior. Cidades com maior utilizacao de servico odontologico tiveram menor proporcao de adolescentes com sangramento gengival e calculo. CONCLUSOES: A utilizacao de servicos odontologicos foi significativamente associada a melhores condicoes de saude gengival (sangramento e calculo). Essa associacao independeu das caracteristicas sociodemograficas individuais e contextuais, e de oclusao dentaria.OBJECTIVE To evaluate the association between gingival health conditions and dental service utilization. METHODS An epidemiological survey of the oral health of 1,799 adolescents was carried out in 35 cities of the state of São Paulo, in 2002. Gingival health was assessed through the prevalence of gingival bleeding on probing and dental calculus (community periodontal index), and dental occlusion was assessed through the dental aesthetic index. The utilization of dental services was measured by means of the dental care index (F/DMFT) for each city. Multilevel logistic regression analysis was used to adjust explanatory models to factors associated with the outcome variables of interest. RESULTS The prevalence of gingival bleeding on probing was 21.5%, whereas dental calculus was prevalent in 19.4%. Male participants, who were either black or dark-skinned, lived in crowded homes, in rural areas, and showed schooling delay, were at a significantly higher risk than their respective counterparts. The following dental occlusion characteristics were also associated with unhealthy gum: incisor segment crowding, vertical anterior open bite, and antero-posterior molar relationship. Cities with a higher utilization of dental services showed a smaller proportion of adolescents with gingival bleeding and dental calculus. CONCLUSIONS The utilization of dental services was significantly associated with better gingival health conditions (gingival bleeding and dental calculus). This association did not depend on contextual and individual sociodemographic characteristics or dental occlusion.

Rabies virus distribution in tissues and molecular characterization of strains from naturally infected non-hematophagous bats

Bats are main reservoirs for Lyssavirus worldwide, which is an important public health issue because it constitutes one of the big challenges in rabies control. Yet, little is known about how the virus is maintained among bats, and the epidemiological relationships remain poorly understood. The aim of the present study was to investigate the distribution of the rabies virus (RABV) in bat tissues and organs and to genetically characterize virus isolates from naturally infected non-hematophagous bats. The heminested reverse transcriptase polymerase chain reaction (hnRT-PCR) and sequencing using primers to the nucleoprotein coding gene were performed. The results showed a dissemination of the RABV in different tissues and organs, particularly in the salivary glands, tongue, lungs, kidneys, bladder, intestine and feces, suggesting other possible forms of RABV elimination and the possibility of transmission among these animals. The phylogenetic analysis confirmed that different variants of RABV are maintained by non-hematophagous bats in nature and have similar tissue distribution irrespective of bat species and phylogenetic characterization.

Dogs and Opossums Positive for Vaccinia Virus during Outbreak Affecting Cattle and Humans, São Paulo State, Brazil

During a vaccinia virus (VACV) outbreak in São Paulo State, Brazil, blood samples were collected from cows, humans, other domestic animals, and wild mammals. Samples from 3 dogs and 3 opossums were positive for VACV by PCR. Results of gene sequencing yielded major questions regarding other mammalian species acting as reservoirs of VACV.

Hepatozoon spp. infections in wild rodents in an area of endemic canine hepatozoonosis in southeastern Brazil

Hepatozoon canis is a tick-borne parasite that occurs worldwide. In rural areas of Brazil, H. canis vectors remain unknown, which has led to speculation about alternative routes of transmission. Small rodents can play a role in the transmission (via predation) of Hepatozoon americanum, which led us to question whether predation might be an alternative mode of transmission for H. canis. Thus, this study investigated whether Hepatozoon spp. are present in wild small rodents in forest fragments that surround rural areas in Botucatu County, São Paulo, Brazil, where canine hepatozoonosis is endemic. The study included blood samples from 158 dogs, which were screened by microscopy and molecular analysis. Blood samples and tissues from 67 rodents were obtained for histopathology and molecular detection. The prevalence of H. canis was high (66.45%) in dogs from rural areas of Botucatu, São Paulo, Brazil. The molecular analysis showed that wild rodent species in Brazil were infected with Hepatozoon spp. other than H. canis. Therefore, although the hypothesis that sylvatic rodents act as reservoirs for H. canis was not supported, the presence of monozoic cysts in the rodents suggests that, in addition to intermediate hosts, wild small rodents in Brazil might act as paratenic hosts of Hepatozoon spp. because they harbor infective stages for intermediate host predators.

Canine distemper virus infection in a lesser grison (Galictis cuja): first report and virus phylogeny

Infectious diseases in wild animals have been increasing as a result of their habitat alterations and closer contact with domestic animals. Canine distemper virus (CDV) has been reported in several species of wild carnivores, presenting a threat to wildlife conservation. We described the first case of canine distemper virus infection in lesser grison (Galictis cuja). A free-ranging individual, with no visible clinical sigs, presented sudden death after one day in captivity. Molecular diagnosis for CDV infection was performed using whole blood collected by postmortem intracardiac puncture, which resulted positive. The virus phylogeny indicated that domestic dogs were the probable source of infection.

Fluorescent antibody test, quantitative polymerase chain reaction pattern and clinical aspects of rabies virus strains isolated from main reservoirs in Brazil

Rabies virus (RABV) isolated from different mammals seems to have unique characteristics that influence the outcome of infection. RABV circulates in nature and is maintained by reservoirs that are responsible for the persistence of the disease for almost 4000 years. Considering the different pattern of pathogenicity of RABV strains in naturally and experimentally infected animals, the aim of this study was to analyze the characteristics of RABV variants isolated from the main Brazilian reservoirs, being related to a dog (variant 2), Desmodus rotundus (variant 3), crab eating fox, marmoset, and Myotis spp. Viral replication in brain tissue of experimentally infected mouse was evaluated by two laboratory techniques and the results were compared to clinical evolution from five RABV variants. The presence of the RABV was investigated in brain samples by fluorescent antibody test (FAT) and real time polymerase chain reaction (qRT-PCR) for quantification of rabies virus nucleoprotein gene (N gene). Virus replication is not correlated with clinical signs and evolution. The pattern of FAT is associated with RABV replication levels. Virus isolates from crab eating fox and marmoset had a longer evolution period and higher survival rate suggesting that the evolution period may contribute to the outcome. RABV virus variants had independent characteristics that determine the clinical evolution and survival of the infected mice.