Probability of occurrence of the Brazilian spotted fever in northeast of Paraná state, Brazil

Abstract

Brazilian spotted fever (BSF) is a fatal zoonosis because of the difficulties in its early diagnosis and treatment. Occurrences of BSF in the northeast of the state of Paraná prompted investigation of areas at risk of this rickettsiosis in the municipalities of Japira, Jaboti, Pinhalão and Tomazina. To determine the areas at risk, 592 serum samples from dogs and 230 from equids were analyzed by means of the indirect immunofluorescence assay (IFA) for Rickettsia rickettsii and R. parkeri . In addition, risk probability maps were drawn up using the kriging indicator technique. Among the samples tested, 5.3% (43/822) indicated presence of antibodies reactive to at least one of the two Rickettsia species tested: 7.8% of the equids (18/230) and 4.2% of the dogs (25/592) were positive. Geostatistical analysis showed that the average seropositivity rate was 5 to 6%. Although the average seropositivity rates observed among these dogs and equids were lower than those reported from endemic areas of Brazil, the biotic components (etiological agent, vector and reservoirs) and environmental aspects of BSF epidemiology were present in these municipalities.Keywords: Rickettsia rickettsii, Rickettsia parkeri, risk map, serology, geostatistical analysis. ResumoA febre maculosa brasileira (FMB) é uma zoonose fatal devido às dificuldades para diagnosticá-la e tratá-la precocemente. A ocorrência de casos de FMB no Estado do Paraná suscitou a investigação de áreas de risco desta rickettsiose nos municípios de Japira, Jaboti, Pinhalão e Tomazina, na mesorregião norte pioneiro do Paraná. Para determinar as áreas de risco foram analisadas amostras de soro de 592 cães e 230 equídeos submetidos à reação de imunofluorescência indireta para Rickettsia rickettsii e R. parkeri. Além disto, foram construídos mapas de probabilidade de risco pela técnica de krigagem indicatriz. Das amostras testadas 5,3% (43/822) continham anticorpos para pelo menos uma das duas rickettsias testadas. Os equídeos apresentaram uma positividade de 7,8% (18/230) e os cães de 4,2% (25/592). A análise geoestatística mostrou que a soropositividade média é de 5 a 6%. Embora as soropositividade médias de cães e equídeos constatadas tenham sido menores do que as relatadas em áreas endêmicas do território brasileiro, os componentes bióticos (agente etiológico, vetor e reservatórios) e ambientais da epidemiologia da FMB se fazem presentes nos municípios referidos.Palavras-chave: Rickettsia rickettsii, Rickettsia parkeri, mapa de risco, sorologia, análise geoestatística.

Biodiversity of Potential Vectors of Rickettsiae and Epidemiological Mosaic of Spotted Fever in the State of Paraná, Brazil

“…provide the comparative results needed for effective public health action. In PR, the first confirmed SFR case occurred in 2006 (14), resulting in a number of subsequent studies in the state (51)(52)(53)(54)(55)(56)(57)(58)(59)(60). The majority of these have provided basic information concerning rickettsia circulation in a given area, with little direct attempt to study case association or use Surveillance System data.…”

Rickettsial infection in equids, opossums and ticks in the municipality of Monte Mor, state of São Paulo, Brazil

“…Other studies have found percentages of seropositive donkeys lower than percentages observed in horses. Horta et al (2004) found 0/4 donkey seropositive to R. rickettsii in Pedreira, a municipality near Monte Mor, and Otomura et al (2016) found 2/45 (4.4%) seropositive donkeys in northeastern Paraná. Although there is no research that evaluated the role of the hybrid equid (Equus caballus x Equus asinus) on the epidemiology of R. rickettsii, it is possible that this animal is not a good sentinel, since donkeys are more resistant to the tick vector A. sculptum than horses (Castagnolli et al, 2003) and the population of mules in the state of São Paulo is small (IBGE, 2017).…”

Dogs (Canis familiaris) as Sentinels for Human Infectious Disease and Application to Canadian Populations: A Systematic Review

“…A serosurvey of dogs and cats in Caratinga was performed ten years after a previous serosurvey had been conducted in order to evaluate the success of vector control measures adopted by public health services, concluding that the vector control had been successful [44]. Occurrences of Brazilian spotted fever in the northeast of Paraná State prompted a risk assessment utilizing serosurveys of dogs, leading to the construction of risk-probability maps using seropositivity rates and known environmental aspects of the municipalities [45]. A seroprevalence study conducted in San José, Costa Rica demonstrated that dogs from areas associated with human cases of SFG rickettsia had greater odds of being seropositive than that of shelter dogs [46].…”