[First autochthonous case of spotted fever associated with the Reserva Ecológica Costanera Sur, Buenos Aires City]. / Primer caso autóctono de fiebre manchada asociado a la Reserva Ecológica Costanera Sur, Ciudad Autónoma de Buenos Aires.

The first autochthonous case of rickettsiosis is reported here. The case occurred in the Costanera Sur Ecological Reserve, a protected area of the City of Buenos Aires, in August 2022, where 4 species of ticks were found, namely Amblyomma aureolatum, Ixodes auritulus sensu lato, Rhipicephalus sanguineus sensu stricto and Amblyomma triste. The epidemiological, ecological, clinical and laboratory aspects that allowed timely diagnosis and appropriate treatment are also described.

Bartonella spp. associated with rodents in an urban protected area, Buenos Aires (Argentina).

At least 15 of the 30 Bartonella species are involved in human pathologies, and several of them are associated with rodents and their fleas. The aims of this study were detect and molecularly characterize the Bartonella infections in rodents from an urban protected area of ​Buenos Aires City (Argentina). A total of 186 rodents were captured and identified. For PCR of the 16S rRNA fragment, 23.7 % of the samples tested positive, and two groups (GrA and GrB) were identified. Likewise, the comparison between the sequences obtained for the gltA gene determined the presence of three genotypes, closely related to Bartonella spp. detected in sigmodontine rodents and their fleas in the Americas, which form a well-separated clade. The high prevalence of Bartonella in rodents from an urban protected area of ​Buenos Aires city is relevant from a public health perspective.

Molecular detection and identification of Bartonella in the cat flea Ctenocephalides felis felis collected from companion animals in a border area in northeastern Argentina.

Molecular methods were used to detect and identify Bartonella species in the cat fleas Ctenocephalides felis felis from Puerto Iguazú, a border area in northeastern Argentina. The fleas were collected from 12 household animals, 9 dogs (Canis lupus familiaris) and 3 cats (Felis silvestris catus) during July 2016. Out of 15C. f. felis analyzed for PCR, only one flea collected from a cat was positive (6.66%) in screened for Bartonella spp. based on the gltA gene. Bartonella clarridgeiae was identified in the genetic analyses, this specimen clustered monophyletically with others B. clarridgeiae isolated from different geographical origins (1.0 PP), even, all shared the same haplotype. The results obtained provide evidence of the presence of B. clarridgeiae in cat fleas from Argentina suggesting the probable presence of related flea-borne diseases in the region and the role of cat fleas in the transmission of Bartonella among mammals including humans.

The presence of Borrelia theileri in Argentina.

The presence of Borrelia theileri in Argentina is confirmed after recording the spirochete from a bovine in northern Argentina. The analysis of sequences of the flagellin gene (fla) and length of Borrelia spp. specimens on thick blood films shows that the local isolate clusters within a well-supported clade with B. theileri isolates from different geographical origins, confirming the presence of B. theileri in Argentina. The mean length of 30 specimens of B. theileri was 12.89 µm (standard deviation 2.88 µm, range 9.35-20.16 µm). The only known vector of Borrelia theileri in northern Argentina is the cattle tick Rhipicephalus microplus, therefore Borrelia infection should be regarded as a potential complication of other cattle tick-borne diseases such as babesiosis, especially on cattle introduced from areas free of R. microplus. The possibility of serologic cross-reaction with B. theileri must not be minimized in studies of other spirochaetes in the R. microplus infested region of Argentina.

Serological evidence of Rickettsia and Coxiella burnetii in humans of Buenos Aires, Argentina.

In Buenos Aires city (Argentina), the circulation of these agents has been detected mainly in vectors and animals, few human cases having been described. The aim of our study was to determine the seroprevalence of Rickettsia (spotted fever--SFG--and typhus--TG--groups) and Coxiella burnetii (Q fever agent) in residents of Buenos Aires city. The study involved 99 participants. Rickettsia IgG antibodies against SFG and TG were detected by IFA in 28.3% and 16.2% of serum samples, respectively. SFG titers were mostly 1/64 (53.6%) with a maximum of 1/512 (3.5%) whereas TG titers ranged between 1/64 (62.5%) and 1/256 (6.3%). Only one sample showed a titer of 1/32 for C. burnetii (phases I and II). The circulation of these pathogens in urban areas such as the city of Buenos Aires should be considered by health services, especially at the primary care level.