Antemortem diagnosis of human rabies in a veterinarian infected when handling a herbivore in Minas Gerais, Brazil

The Ministry of Health's National Human Rabies Control Program advocates pre-exposure prophylaxis (PEP) for professionals involved with animals that are at risk of contracting rabies. We report an antemortem and postmortem diagnosis of rabies in a veterinarian who became infected when handling herbivores with rabies. The antemortem diagnosis was carried out with a saliva sample and a biopsy of hair follicles using molecular biology techniques, while the postmortem diagnosis used a brain sample and conventional techniques. The veterinarian had collected samples to diagnose rabies in suspect herbivores (bovines and caprines) that were subsequently confirmed to be positive in laboratory tests. After onset of classic rabies symptoms, saliva and hair follicles were collected and used for antemortem diagnostic tests and found to be positive by RT-PCR. Genetic sequencing showed that the infection was caused by variant 3 (Desmodus rotundus), a finding confirmed by tests on the brain sample. It is essential that professionals who are at risk of infection by the rabies virus undergo pre-exposure prophylaxis. This study also confirms that molecular biology techniques were used successfully for antemortem diagnosis and therefore not only allow therapeutic methods to be developed, but also enable the source of infection in human rabies cases to be identified accurately and quickly.

BAT-BORNE RABIES IN LATIN AMERICA

The situation of rabies in America is complex: rabies in dogs has decreased dramatically, but bats are increasingly recognized as natural reservoirs of other rabies variants. Here, bat species known to be rabies-positive with different antigenic variants, are summarized in relation to bat conservation status across Latin America. Rabies virus is widespread in Latin American bat species, 22.5%75 of bat species have been confirmed as rabies-positive. Most bat species found rabies positive are classified by the International Union for Conservation of Nature as “Least Concern”. According to diet type, insectivorous bats had the most species known as rabies reservoirs, while in proportion hematophagous bats were the most important. Research at coarse spatial scales must strive to understand rabies ecology; basic information on distribution and population dynamics of many Latin American and Caribbean bat species is needed; and detailed information on effects of landscape change in driving bat-borne rabies outbreaks remains unassessed. Finally, integrated approaches including public health, ecology, and conservation biology are needed to understand and prevent emergent diseases in bats.

VIROLOGICAL AND SEROLOGICAL DIAGNOSIS OF RABIES IN BATS FROM AN URBAN AREA IN THE BRAZILIAN AMAZON

The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.

Epidemology and clinical aspects of human rabies in Minas Gerais, Brasil: misdiagnosis and misunderstandings on the psychopathological disturbances

This paper reports 40 cases of human rabies studied at the Carlos Chagas Hospital of UFMC, State of Minas Gerais, Brazil, from 1963 through 1976. From the epidemioiogical point of view it is concluded that the magnitude of the problem of human rabies in underdeveioped countries remains quite unknown. Speciai emphasis is given to the lack of apropriate knowledge of the recommended preventive measures, and to the influence of health education and socio-economic-cultural structure of the communities. The classic clinical picture of human rabies is briefiy described, particular attention being drawn to psychopathologic features of rabies encephalomyeiitis. it is pointed out that in some cases the mental symptoms may predominate from the onset of the illness, adding difficuity to the diagnosis. According to the Authors, human rabies must be differentiated from several psychopathologic syndromes and also from encephalomyelitis due to other central nervous system infections. It is discussed whether the fataiistic concept of human rabies would be somehow contributing to delay a better understanding of the natural history of the disease.

Effect of a booster-dose of rabies vaccine on the duration of virus neutralizing antibody titers in bovines

Humoral immune response using inactivated rabies vaccine was studied in 35 nelore cross-bred bovines of western region of São Paulo state. Ninety days after vaccination, 13 (92.8%) animals presented titers 30.5IU/ml, through mouse neutralization test. After 180 days, 9 (64.3%) sera showed titers 30.5IU/ml, after 270 days, only one (7.1%) showed a titer of 0.51IU/ml, and after 360 days, all animals showed titers < 0.5IU/ml. Group of animals receiving booster dose 30 days after vaccination presented, two months after, all with titers > 0.5IU/ml. At 180 days, 17 (80.9%) sera presented titers > 0.5IU/ml; at 270 days, 15 (71.4%), with titers 30.5IU/ml and at 360 days, 4 (19.0%), with titers 30.5IU/ml. Booster-dose ensured high levels of neutralizing antibodies for at least three months, and 240 days after revaccination, 71.4% of animals were found with titers 30.5IU/ml.

Influence of canine brain decomposition on laboratory diagnosis of rabies

Canine brains infected with rabies virus were submitted to decomposition by being left at room temperature of 25 to 29oC for up to 168h. At 24h intervals, brain fragments were analyzed by immunofluorescence (IF) and by the mouse intracerebral inoculation (MI) test to confirm the diagnosis of rabies and to measure the putrefaction effect on the accuracy of the diagnosis. Forty eight h after the beginning of the experiment, the MI test showed signs of impairment with four negative results, while after 72h, 100% of the results were negative to the MI test and only one result was negative to the IF test, indicating that the threshold period for accurate diagnosis is 24 to 48h before putrefaction. The authors recommend the shipment of suspected cases of rabies to the laboratory for confirmation, but the use of putrid materials for diagnosis is meaningless because of false-negative results.

Outbreak of aggressions and transmission of rabies in human beings by vampire bats in northeastern Brazil

Outbreaks of attacks upon human beings by vampire bats seems to be a common phenomenon in several regions of Latin America, but the occurrence of rabies infection among humans bled by vampires, is relatively low. In the present study, two outbreaks of human rabies transmitted by common vampire bats (Desmodus rotundus) are described from Bahia State, Northeasthern Brazil, in 1991 and 1992. The first was recorded in Aporá where 308 people were bled by vampire bats and three of these die from this zoonosis. The 2nd outbreak occurred in Conde where only five people were bled by vampires, and two deaths by rabies were registered. Our data suggest that rabies transmitted by bats basically depends on the presence of virus in the vampire bat population and not on the number of humans bled by them.

Adverse reactions associated with a Fuenzalida-Palacios rabies vaccine: a quasi-experimental study

The Fuenzalida-Palacios rabies vaccine has been used in South America for rabies post-exposure prophylaxis. To determine the frequency of adverse reactions associated with this vaccine compared to a control group a quasi-experimental study was carried out in Uberlândia, Brazil, from May 1997 to April 1998. Victims of bites or other injuries by dogs or other mammals and who received or not post-exposure prophylaxis with Fuenzalida-Palacios rabies vaccine were compared as to the occurrence of a list of signs and symptoms. Out of 2,440 victims of bites and other injuries from dogs and other mammals 2,114 participated in the study; 1,004 of them provided follow-up information within 10 to 15 days. Headache and pain at the injection sites were the most commonly found symptoms (125/1,000). No neuroparalytic event was detected. Patients who were given Fuenzalida-Palacios rabies vaccine and those who were not had similar incidences of symptoms (risk ratios close to 1). Regarding the occurrence of adverse reactions, Fuenzalida-Palacios rabies vaccine is a valid alternative for rabies post-exposure prophylaxis.

Canine rabies epidemiology in Araçatuba and neighborhood, Northwestern São Paulo State - Brazil

Epidemiological characteristics of canine rabies in the northwest region of São Paulo State (Araçatuba region), Brazil, from 1993 to 1997 are presented. Out of 1,984 dogs, a total of 351 (17.7%) were positive for rabies diagnosis; 89% (312/351) of these occurred in urban areas and 85% (266/312) of the urban positive cases were among owned dogs. The mean age of the rabid dogs was 34 months and 61% were male. Aggressive behavior was observed in 77% of rabid dogs, followed by lack of coordination and paralysis (42%) and 48% of these dogs were responsible biting people or other animals. Information about vaccination status was obtained from 182 records and 51% of rabid dogs were non-vaccinated. The number of unvaccinated rabid dogs indicates a low vaccination index and this factor added to the high dog/man ratio must have contributed to the canine rabies epizootic observed in the studied area.

Digoxigenin-labeled probe for rabies virus nucleoprotein gene detection

A digoxigenin-labeled probe was produced from the Pasteur virus strain for the detection of the rabies virus N gene. The probe hybridization was performed from amplified N gene obtained by reverse transcription polymerase chain reaction and the results by RT-PCR and hybridization showed 100% agreement. The hybridization, when carried out in products amplified by RT-PCR, increases the sensitivity of this technique even more and confers specificity to the diagnosis. The technique described in this work will be useful in rabies diagnosis laboratories, once the cost is compatible with traditional rabies diagnostic techniques.

Human exposure to potential rabies virus transmitters in Olinda, State of Pernambuco, between 2002 and 2006

The aim of the present study was to evaluate the data on human exposure to potential rabies virus transmitters in Olinda, State of Pernambuco, Brazil. Data from 7,062 patients who underwent antirabies prophylactic treatment in Olinda between 2002 and 2006 were analyzed. As expected, dogs and cats were involved in most of the cases; i.e. 82.3 and 16.3%, respectively. Attacks by nonhuman primates, bats and other species (unspecified) were also reported. Among the 7,062 patients who underwent antirabies treatment, 582 patients abandoned the treatment, either by indication from the health unit (195) or by their own decision (387). In conclusion, this study has indicated that prophylaxis for human rabies in this urban area will require a multifaceted approach, including health education, post-exposure prophylaxis, systematic vaccination for dogs and cats, and possibly selective control over wild animals such as hematophagous bats.

Genetic characterization of rabies virus isolated from bovines and equines between 2007 and 2008, in the States of São Paulo and Minas Gerais

INTRODUCTION: Rabies is an acute disease of the central nervous system and is responsible for the deaths of thousands of humans, wild animals and livestock, particularly cattle, as well as causing major economic losses. This study describes the genetic characterization of rabies virus variants that circulate in Desmodus rotundus populations and are transmitted to herbivores. METHODS: Fifty rabies virus isolates from bovines and equines in the States of São Paulo and Minas Gerais, Brazil, were genetically characterized and compared with sequences retrieved from GenBank. RESULTS: Two clusters (I and II) with mean nucleotide identities of 99.1 and 97.6% were found. The first of these contained nearly all the samples analyzed. Lineages from other Brazilian states grouped in cluster II. CONCLUSIONS: Analysis of the amino acid sequences of the N proteins revealed the existence of genetic markers that may indicate possible variations between geographic regions, although the biologically active regions are conserved within the species over space and time.

Rabies diagnosis and serology in bats from the State of São Paulo, Brazil

INTRODUCTION: Bats are one of the most important reservoirs and vectors of the rabies virus in the world. METHODS: From 1988 to 2003, the Zoonosis Control Center in São Paulo City performed rabies diagnosis on 5,670 bats by direct immunofluorescent test and mouse inoculation test. Blood samples were collected from 1,618 bats and the sera were analyzed using the rapid fluorescent focus inhibition test to confirm rabies antibodies. RESULTS: Forty-four (0.8%) bats were positive for rabies. The prevalence of rabies antibodies was 5.9% using 0.5IU/ml as a cutoff. Insectivorous bats (69.8%) and bats of the species Molossus molossus (51.8%) constituted the majority of the sample; however, the highest prevalence of antibodies were observed in Glossophaga soricina (14/133), Histiotus velatus (16/60), Desmodus rotundus (8/66), Artibeus lituratus (5/54), Nyctinomops macrotis (3/23), Tadarida brasiliensis (3/48), Carollia perspicillata (3/9), Eumops auripendulus (2/30), Nyctinomops laticaudatus (2/16), Sturnira lilium (2/17) and Eumops perotis (1/13). The prevalence of rabies antibodies was analyzed by species, food preference and sex. CONCLUSIONS: The expressive levels of antibodies associated with the low virus positivity verified in these bats indicate that rabies virus circulates actively among them.

First report of rabies infection in bats, Molossus molossus, Molossops neglectus and Myotis riparius in the city of São Paulo, State of São Paulo, southeastern Brazil

INTRODUCTION: This paper presents the first report of rabies in three bat species, Molossus molossus, Molossops neglectus and Myotis riparius in the city of São Paulo, Brazil. METHODS: Bats were diagnosed as positive for rabies using the fluorescent antibody test and mouse inoculation test. The isolates were characterized antigenically using a panel of eight monoclonal antibodies. The samples were also genetically analyzed by partial sequencing of the portion of nucleoprotein gene between positions 1157 and 1445nt. RESULTS: Analysis of the results verified that the sample isolated from the species M. molossus presented antigenic variant 6, while the other two samples showed a different profile from that established in the panel, one not previously reported in the literature. The results of genetic analysis revealed that the M. molossus sample segregated with Lasiurus sp. isolates, M. neglectus segregated with a subgroup of Eptesicus furinalis isolates and the Myotis riparius sample segregated with Myotis sp. isolates. CONCLUSIONS: The cases reported in this paper emphasize the need for clarification of the circumstances in which cases of rabies in wildlife occur, principally in urban areas.

Rabies virus in Molossus molossus (Chiroptera: Molossidae) in the State of Pernambuco, Northeastern Brazil

Rabies virus was detected in bats (Molossus molossus) from an urban area in the City of Recife, State of Pernambuco, Brazil. Four individuals were found during the day in visible, non-habitual places, lying on the ground, but still alive. No contact occurred with people or animals. Of these, only two were identified; it was not possible to identify two specimens, since they were incinerated prior to identification. Diagnosis was positive by direct immunofluorescence and intracerebral inoculation in mice. This study presents the first instance in which the virus was detected in insectivorous bats in the State of Pernambuco.