Microorganisms in ticks (Acari: Ixodidae) collected on marsupials and rodents from Santa Catarina, Paraná and Mato Grosso do Sul states, Brazil.

Information about tick fauna and monitoring of pathogen prevalences in ticks (Acari: Ixodidae) in various habitat types can enhance knowledge about the epidemiology of tick-borne pathogens in Brazil. This work shows the results of a study of tick parasitism of wild rodents and marsupials collected in seven localities in the southern part of Brazil, within Atlantic Forest and Cerrado biomes. A total of 61 ticks were collected from small mammals, and after identification to the species level, the ticks were individually tested for the presence of bacteria of the genera Rickettsia, Borrelia, family Anaplasmataceae, and protozoa of the genus Babesia. The following species of ticks were found: Amblyomma ovale Koch, 1844, Amblyomma dubitatum Neumann, 1899, Amblyomma fuscum Neumann, 1907, Ixodes aragaoi Fonseca, 1935, Ixodes fuscipes Koch, 1844, Ixodes loricatus Neumann, 1899, and Ixodes schulzei Aragão and Fonseca, 1951. Among tested ticks, no DNA of Borrelia, Babesia or Anaplasmataceae was detected. Two nymphs of A. ovale were found infected with Rickettsia bellii and four nymphs of I. aragaoi with Rickettsia sp., genetically close to Rickettsia monacensis, Rickettsia tamurae and the endosymbiont Rickettsia spp., previously found in various Ixodidae. In one nymph of A. fuscum, DNA of a novel Hepatozoon sp. was found. Additionally we provide novel tick-host associations.

Population ecology of hantavirus rodent hosts in southern Brazil.

In this study we analyze population dynamics of hantavirus rodent hosts and prevalence of infection over a 2-year period in Southern Brazil, a region with a high incidence of hantavirus pulmonary syndrome. The 14 small mammal species captured were composed of 10 rodents and four marsupials, the six most abundant species being Akodon serrensis, Oxymycterus judex, Akodon montensis, Akodon paranaensis, Oligoryzomys nigripes, and Thaptomys nigrita. These species displayed a similar pattern with increasing population sizes in fall/winter caused by recruitment and both, increase in reproductive activity and higher hantavirus prevalence in spring/summer. Specific associations between A. montensis/Jaborá Virus (JABV) and O. nigripes/Juquitiba-like Virus (JUQV-like) and spillover infections between A. paranaensis/JABV, A. serrensis/JABV, and A. paranaensis/JUQV-like were observed. Spillover infection in secondary hosts seems to play an important role in maintaining JABV and JUQV-like in the hantavirus sylvatic cycle mainly during periods of low prevalence in primary hosts.

Characterization of Juquitiba virus in Oligoryzomys fornesi from Brazilian Cerrado.

The Juquitiba virus, an agent of Hantavirus Cardiopulmonary Syndrome, is one of the most widely distributed hantavirus found in South America. It has been detected in Oligoryzomys nigripes, Akodon montensis, Oxymycterus judex, Akodon paranaensis in Brazil and in O. nigripes, Oryzomys sp. and Oligoryzomys fornesi rodents in Argentine, Paraguay and Uruguay. Here, we report the genomic characterization of the complete S segment from the Juquitiba strain, isolated from the lung tissues of O. fornesi, the presumed rodent reservoir of Anajatuba virus in Brazilian Amazon, captured in the Cerrado Biome, Brazil.