Factors associated with epidemiology of Anaplasma platys in dogs in rural and urban areas of Minas Gerais State, Brazil.

This epidemiological survey of Anaplasma platys was carried out in rural and urban areas of three distinct regions of the State of Minas Gerais, Brazil. EDTA blood samples were collected during the dry season from dogs living on farms with an attempt to resample the same dogs in the subsequent rainy season. Samples were also taken from dogs in urban areas. DNA was extracted from blood samples for real time PCR. Risk factors, such as age, breed, sex, presence of ticks, and packed cell volume were analyzed. During the rainy season, the prevalence of infection by A. platys in dogs in the rural areas was significantly higher (13.9%) than that observed in dogs in the urban areas (5.1%). Dogs in the Nanuque region were 3.74 times (p=0.001) more likely to be real-time PCR positive than dogs in the other two studied regions. Dogs infested with ticks showed higher rates of positivity. The results showed that in rural areas of Minas Gerais A. platys infection is influenced by climatic conditions. In areas of higher temperature and higher humidity, transmission occurs during both the dry and rainy seasons, while in areas with lower temperature and humidity transmission occurs mainly during the dry season.

Use of a Real Time PCR for detecting subspecies of Babesia canis.

This paper reports the development and use of a Real Time PCR for detection of Babesia canis canis, B. canis rossi, and B. canis vogeli in endemic areas of Brazil. The sequences of the internal transcribed spacer (ITS) of several organisms were aligned and five primers and four probes were designed for amplification of a fragment (around 125 bp) which differentiates subspecies of B. canis. Blood samples collected from dogs living in farms in three distinct rural regions within the State of Minas Gerais (Lavras, Belo Horizonte and Nanuque) were tested. Blood samples had been collected during a dry season (Lavras, n=100; Belo Horizonte, n=50; Nanuque, n=102); the dogs were re-sampled in the subsequent rainy season (Lavras, n=71; Belo Horizonte, n=29; Nanuque, n=66). From each sample, DNA was extracted and Giemsa stained smears were microscopically examined for direct detection of Babesia parasites. B. canis vogeli was the only subspecies found, with an overall prevalence of 9.9% during the dry season and 10.8% during the rainy season. Dogs living in Nanuque and Belo Horizonte showed significantly higher prevalence rates than those living in Lavras (13.7%, 12.0% and 5.0%, respectively). The Real Time PCR developed proved to be appropriate to detect B. canis subspecies in endemic areas.

Canine babesiosis caused by Babesia canis vogeli in rural areas of the State of Minas Gerais, Brazil and factors associated with its seroprevalence.

This epidemiological survey on canine babesiosis was carried out in three distinct rural regions (Lavras, Belo Horizonte and Nanuque) of the State of Minas Gerais, Brazil. Ticks and blood samples were collected during a dry season (Lavras, n=92; Belo Horizonte, n=50; Nanuque, n=102) and the subsequent rainy season (Lavras, n=71; Belo Horizonte, n=28; Nanuque, n=66) from dogs living on farms. Plasma samples were analyzed by the indirect fluorescent antibody test for detection of anti-Babesia canis vogeli antibodies. DNA was extracted from blood of serologically positive dogs and molecular characterization of Babesia species was performed. Rhipicephalus sanguineus, Amblyomma cajennense and Boophilus microplus were the tick species identified in all regions. In Lavras, in addition to those tick species, A. tigrinum and A. ovale were also identified. The most prevalent tick species was A. cajennense (35.3%), followed by R. sanguineus (19%) and B. microplus (4.0%). Dogs living in Nanuque region were more heavily infested with ticks than dogs living in Belo Horizonte and Lavras regions. The overall frequency of anti-B. c. vogeli antibodies in the canine population in rural areas of Minas Gerais was 28.7%, with prevalence rates of 49.0% in Nanuque, 34.0% in Belo Horizonte and 3.3% in Lavras. The age of the animals and tick infestation were associated with seroprevalence of B. c. vogeli. The sequence analysis showed that B. c. vogeli was the only Babesia species present in all three regions. This study showed different rates of prevalence and incidence of canine babesiosis among the three rural regions sampled in Minas Gerais State. The results point to the importance of canine babesiosis in rural areas and to the need for further studies related to its transmission and maintenance in nature.