Molecular and Serological Characterization of Pathogenic Leptospira Spp. Isolated From Symptomatic Dogs in a Highly Endemic Area, Brazil

Abstract

Background: Leptospirosis is an endemic zoonosis in Brazil, with great impact in human and animal health. Although dogs are frequently infected by pathogenic Leptospira, the current epidemiological understanding of canine leptospirosis is mainly based on serological tests that predict the infecting serogroup/serovar. Thus, the present study aimed at identifying the causative agent for severe cases of canine leptospirosis in a highly endemic area through the isolation and characterization of the isolated strains. Results: Urine, serum and blood samples were collected from 31 dogs with suspected acute leptospirosis treated at the Veterinary Hospital Service of Santo Amaro University between 2018 and 2019. Acute infection was confirmed in 17 dogs (54.8%) by the associated use of Polymerase Chain Reaction (PCR), Microscopic Agglutination (MAT) and bacteriological culture. Eleven dogs (35.5%) had titers ≥800, with the most frequent serogroups being Autumnalis and Icterohaemorrhagiae (n = 4 each) and Canicola (n = 2). Leptospires were recovered from four dogs, and Multilocus Sequence Analysis (MLSA) revealed infection caused by L. interrogans, which were further characterized as serogroups Canicola (n=1) and Icterohaemorrhagiae (n=3). Conclusion: The identification of circulating strains in poverty-stricken locations with humans living in rural-urban interfaces may assist local authorities to implement effective prevention policies. The identity of the isolates and serological pattern of MAT titers found among the suspected dogs suggest that dogs are highly exposed to the serogroup Icterohaemorrhagiae, also indicating possible circulation of serogroups not yet isolated in Brazil, notably serogroup Autumnalis.

Insights on seroprevalence of leptospirosis in dogs and cats from people with animal hoarding disorder profile in a semiarid region of Brazil

“…Canicola serogroup was the second most frequent in dogs, which reinforces the risk of intradomiciliary infection for humans, a fact that has been previously reported (BENITEZ et al, 2021). Autumnalis serogroup has already been reported in severe cases of canine leptospirosis (SANTOS et al, 2021), as well as being described as the second most frequent in stray and public shelter attended dogs (MIOTTO et al, 2018). In Japan, two cases of leptospirosis in humans caused by the serogroup Autumnalis were reported (KOIZUM et al, 2020).…”

One health: a comprehensive approach to improve prevention and control strategies in Leptospirosis

“…Epidemiological importance of the canine species in leptospirosis allows us to understand the variables related to the acquisition of the disease. This is important for the design of control policies and the number of annual deaths in humans and canines exposed to risk factors such as living with infected animals, relationship with environments contaminated with spirochete, and wild animals (MARAMI et al 2021, SANTOS et al 2021.…”

Investigating Leptospira dynamics in a multi‐host community using an agent‐based modelling approach

“…Moreover, urban slums in developing countries support high densities of peridomestic and domestic species like rodents and dogs that are known reservoirs or vectors of pathogenic Leptospira strains. Dogs in such settings are mostly free‐roaming, with access to contaminated environments as well as a higher likelihood of contacting wild or peridomestic rodent species that may also harbour dog‐adapted or other host species‐adapted strains (Santos et al., 2021). Dogs can thus play a vital role in the zoonotic transmission of leptospirosis, either as reservoir or maintenance hosts or as vectors (Brod et al., 2005; Gay et al., 2014; Sykes et al., 2011; Zaidi et al., 2018).…”