Epidemiologia descritiva da raiva dos herbívoros notificados no estado do Paraná entre 1977 e 2012

Abstract

RESUMO.-Realizou-se estudo epidemiológico descritivo da raiva dos herbívoros no estado do Paraná entre os anos de 1977 e 2012. Os casos confirmados de raiva e o total de amostras de encéfalo encaminhadas para o diagnóstico foram distribuídos por espécie, por ano, por meses, por mesorregião geográfica e por municípios, aplicando-se o teste de Qui-quadrado para verificar se havia associação com esses fatores. Modelo probabilístico foi ajustado à sé-rie histórica para verificação de padrões cíclico ou sazonal. Comprovou-se que a raiva é uma doença endêmica no PR, com ocorrência variável entre os anos, sem padrão sazonal e com ciclicidade aparente a cada 18 anos, acometendo, sobretudo, bovinos (86,9%) e equídeos (11,3%). Verificou--se grande difusão no estado (47,6% dos municípios), e a maior expansão geográfica aconteceu na última década. A descriptive epidemiological survey of rabies in herbivorous reared in the state of Parana, Brazil, was carried out from 1977 to 2012. The positive cases and the total number of brain samples processed for diagnostic purposes were distributed according to species, year, month, geographical region and municipality. Chi-square test was used to verify if rabies was associated to these factors. Probabilistic model was applied to historical series in order to verify cyclic and seasonal patterns. In Parana, rabies is an endemic disease with variable yearly occurrence, without seasonal pattern and with a possible cyclic pattern every 18 years. Cattle (86.9%) and equides (11.3%) were mainly affected. Rabies was registered in 47.6% of all municipalities, indicating a great spread of this disease in Parana, mainly during the last decade. Middlewest and Curitiba regions, followed by Pioneer North and West regions, were the areas of most occurrence. The number of cases per municipality was weakly correlated with the number of shelters for Desmodus rotundus (r=0.469; p<0.0001). Therefore, we suggest that annual immunization of cattle and equides should be applied in the high occurrence areas (Middlewest and Curitiba regions) and encouraged in intermediate occurrence areas (Pioneer North and West regions).

Epidemiological study of rabies in cattle in southern Brazil: spatial and temporal distribution from 2008 to 2017

“…The disease has epidemic characteristics in most of the months analyzed from 2012 to 2014, remaining endemic over the other years (2011, 2015, and 2016) with eventual short periods of epidemics. Other works have shown that rabies is endemic in cattle, presenting variable incidence over the years, with a few epidemic periods throughout the years (Dognani et al 2016), unlike the findings of this study. In addition, we observed that, as the disease incidence in animals and estates increased, the virus spread geographically to most of the municipalities (54.16%) in the LRD area of influence.…”

“…Menezes et al (2008) found similar results in a study conducted in Minas Gerais from 1998 to 2006. Another study carried out in Paraná from 1977 to 2012 observed the absence of trend and seasonality (Dognani et al 2016). Additionally, although some works carried out in the state of RS have suggested that most cases of rabies occur between fall and winter (Marcolongo-Pereira et al 2011) and spring and summer months (Rech et al 2006), the disease does not present seasonality in the southern region of RS (p>0.05).…”

“…These results suggest the cyclicity of rabies in this region, although this is not statistically proven. A study conducted in the state of Paraná over a period of 35 years suggests cyclicity of the disease every 18 years (Dognani et al 2016). On the other hand, studies conducted in the states of Mato Grosso do Sul (Mori & Lemos 1998, Neves 2008, Ribas et al 2013, São Paulo (Gomes et al 2011), and Paraíba (Galiza et al 2010) suggest a period of 5-7 years for cyclicity of rabies in cattle.…”

“…This data shows that the virus spread to areas without prior record of the disease. This may have been due to a lack of measures against the bat populations that survive under favorable conditions and cross geographical barriers, favoring dissemination of the virus (Fernandes & Riet-Correa 2007, Gomes et al 2011, Dognani et al 2016) and a lack of systematic preventive vaccination of the cattle. From 2015, the number of municipalities experiencing outbreaks dropped again, which is probably due to the control measures undertaken in view of the outbreaks diagnosed in the previous years.…”

Bovine rabies: economic loss and its mitigation through antirabies vaccination

“…In a thirty-five-year retrospective study conducted in the Central region of Rio Grande do Sul, 151 cases of bovine rabies were diagnosed, in a total of 6,021 examined materials (49.5%) in the routine diagnostic service. A retrospective 16-year study conducted in the state of Paraná (Dognani et al 2016) describes the occurrence of 2,331 (30.6%) cases in a total of 7,627 bovine samples examined. Another 16-year retrospective study was conducted in Rio Grande do Sul (Teixeira et al 2008), in which 670 cases of rabies were diagnosed within a total of 1,729 samples (38.7%).…”