Seroprevalence and risk factors for infection with Bartonella bacilliformis in Loja province, Ecuador

First report of Bartonella henselae and Bartonella clarridgeiae carriage in stray cats from Ecuador and its link to a cat scratch disease outbreak in 2022

INTRODUCTION

The genus Bartonella includes species and subspecies of fastidious, facultative intracellular Gram-negative bacilli that infect a wide variety of mammalian reservoirs including cats and humans. In 2022, the Ecuadorian Ministry of Health reported an outbreak of cat scratch disease caused by B. henselae in the city of Guayaquil. Therefore, we aimed to characterize the presence of Bartonella spp. in domestic and stray cats from the area of Guayaquil where the outbreak happened in 2022.

METHODS

Whole blood samples of 100 domestic and stray cats were collected. Riboflavin synthase (ribC) and 16S rRNA genes detection was performed by PCR using Bartonella spp. specific primers, followed by Sanger sequencing and phylogenetic analysis.

RESULTS

14 cats were positive for Bartonella spp. carriage. Phylogenetic analysis confirmed the presence of 12 cats infected with B. henselae and 2 cats with B. clarridgeiae.

CONCLUSIONS

There is a high prevalence of Bartonella spp. carriage in cats in the city of Guayaquil within the area where a recent cat scratch disease outbreak happened. Considering the high presence of cats and other domestic and stray animals in the city of Guayaquil, a One Health approach for surveillance and prevention of zoonotic diseases like cat scratch disease is needed.

Bartonella spp. detection in ticks, Culicoides biting midges and wild cervids from Norway

Bartonella spp. are fastidious, gram-negative, aerobic, facultative intracellular bacteria that infect humans, and domestic and wild animals. In Norway, Bartonella spp. have been detected in cervids, mainly within the distribution area of the arthropod vector deer ked (Lipoptena cervi). We used PCR to survey the prevalence of Bartonella spp. in blood samples from 141 cervids living outside the deer ked distribution area (moose [Alces alces, n = 65], red deer [Cervus elaphus, n = 41] and reindeer [Rangifer tarandus, n = 35]), in 44 pool samples of sheep tick (Ixodes ricinus, 27 pools collected from 74 red deer and 17 from 45 moose) and in biting midges of the genus Culicoides (Diptera: Ceratopogonidae, 120 pools of 6,710 specimens). Bartonella DNA was amplified in moose (75.4%, 49/65) and in red deer (4.9%, 2/41) blood samples. All reindeer were negative. There were significant differences in Bartonella prevalence among the cervid species. Additionally, Bartonella was amplified in two of 17 tick pools collected from moose and in 3 of 120 biting midge pool samples. The Bartonella sequences amplified in moose, red deer and ticks were highly similar to B. bovis, previously identified in cervids. The sequence obtained from biting midges was only 81.7% similar to the closest Bartonella spp. We demonstrate that Bartonella is present in moose across Norway and present the first data on northern Norway specimens. The high prevalence of Bartonella infection suggests that moose could be the reservoir for this bacterium. This is the first report of bacteria from the Bartonella genus in ticks from Fennoscandia and in Culicoides biting midges worldwide.

Carrion's disease: more than a neglected disease

Infections with Bartonella bacilliformis result in Carrion's disease in humans. In the first phase of infection, the pathogen causes a hemolytic fever ("Oroya fever") with case-fatality rates as high as ~90% in untreated patients, followed by a chronical phase resulting in angiogenic skin lesions ("verruga peruana"). Bartonella bacilliformis is endemic to South American Andean valleys and is transmitted via sand flies (Lutzomyia spp.). Humans are the only known reservoir for this old disease and therefore no animal infection model is available. In the present review, we provide the current knowledge on B. bacilliformis and its pathogenicity factors, vectors, possible unknown reservoirs, established and potential infection models and immunological aspects of the disease.