Sero‐epidemiology of Canine Leptospirosis in Trinidad: Serovars, Implications for Vaccination and Public Health

Abstract

A sero-epidemiological study on canine leptospirosis was conducted in house, stray, farm and hunting dogs, as well as in suspect cases of clinical canine leptospirosis. Serum samples were collected from apparently healthy (vaccinated and nonvaccinated), house dogs. A questionnaire was administered to the owners to elicit information on risk factors for leptospirosis. The microscopic agglutination test was used to screen for leptospirosis using 17 international serovars. Reciprocal titres of between 100 and <800 were considered as evidence of past exposure while reciprocal titres of 800 or greater were classified as suggestive of acute/current infection. Of a total of 419 serum samples tested, 61 (14.6%) were seropositive for Leptospira agglutinins, 23 (5.5%) had mixed infections and 16 (3.8%) had current infection. Amongst 50 suspected cases of clinical leptospirosis, 24 (48.0%) were seropositive and only 13 (26.0%) had current infection compared with 10 (6.3%) and three (1.9%) of 160 apparently healthy house dogs respectively. The difference was statistically significant (P < 0.05; v 2 ). Twelve (25.5%) of 47 hunting dogs, 10 (20.4%) of 49 farm dogs and five (4.4%) of 113 stray dogs were seropositive (P < 0.05; v 2 ). Overall, a total of nine serovars were detected with serovars mankarso, icterohaemorrhagiae RGA, autumnalis and copenhageni being involved in 29 (47.5%), 20 (32.8%), 25 (41.0%) and 10 (16.4%) respectively in 61 seropositive dogs (P < 0.05; v 2 ). Serovar mankarso was most predominant in seropositive apparently healthy dogs, 37.8% (14/37), suspected clinical cases of leptospirosis, 62.5% (15/24) compared with serovar icterohaemorrhagiae with a frequency of 21.6% (8/37) and 50.0% (12/24), the difference being statistically significant (P < 0.05; v 2 ). Although all vaccines used for prevention of canine leptospirosis in the country contain serovars canicola and icterohaemorrhagiae, serovar mankarso was mostly associated with infection and disease and may be a good candidate for inclusion in the vaccine used locally. The public health risk posed to owners of dogs infected with Leptospira cannot be over-emphasized considering the zoonotic nature of the disease.

Correspondence

“…In the acute clinical form of canine leptospirosis, members of Icterohaemorrhagiae are most commonly reported as serovar Copenhageni in Trinidad [1] and Australia [7] or Icterohaemorrhagiae in Japan [8] and Brazil [9].…”

Association of prevalent Leptospira species with different rodents of three northern provinces in Iran using microscopic agglutination test

“…In the majority of studies, it has been shown that farmers are usually involved in disease in comparison with other professions. In the study of Perret et al (2005) in Chile, the incidence rate of the disease among the farmers was reported 72% [16]. Slack et al (2010) had mentioned that the most important risk factors of this disease were occupational factors, direct or indirect contact with the animals or their dead bodies, with grass and bushes, swimming, hunting, aquatic sports, and traveling to hot and rainy areas, suggesting the important influence of the type of occupation on the disease outbreak [1,17].…”

Canine Leptospirosis Serology in Southern Mexico City

“…According to Adesiyuncriteria [11], for determining leptospirosis infection, 5 dogs with dilution titers between 1:800 and 1:3200 at the moment of the study coursed with acute leptospirosis, and leptospipuria could contaminate their surroundings, facilitating the disease's transmission to other mammals, such as rats, dogs and even humans. The same authors mention that low titers of 1:100 and 1:200 are considered to be indicative of immunological anamnesis due to a previous infection of the animal.…”

“…The animal's reproductive age and the Leptospira seropositivity are possibly related to sniffing habits and the licking of external genitalia by infected males and females in heat [14] [21]. However, older dogs are more likely to have been exposed to leptospirosis at some point and, therefore, are likely to present antibodies for different serotypes due to immunological anamnesis [11].…”

“…Serologic tests conducted on canine population in different urban environments report a 24.9% seroprevalence in Michigan, USA. [7], 29.4% in Milan, Italy [8], 10.5% in Itapema, Brazil [9], 41.1% in Cali, Colombia [10], 14.6% in Trinidad and Tobago [11], and 22% in Guelph, Canada [12]. The most common serotypes in urban environments are: Canicola, Icterohaemorrhagiae, Grippotyphosa, and Pomona [6] [10] [12] [13].…”