The Seal Tuberculosis Agent, Mycobacterium Pinnipedii, Infects Domestic Cattle in New Zealand: Epidemiologic Factors and Dna Strain Typing

Abstract

ABSTRACT:The fur seal (Arctocephalus forsteri), which is abundant in coastal areas of New Zealand, harbors several zoonotic pathogens, including Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex. We describe the microbiology and epidemiology of seven cases of M. pinnipedii infection in beef cattle (Bos primigenius) in coastal areas of New Zealand in 1991-2011. Epidemiologic factors were analyzed on six case farms and a telephone survey of 55 neighboring farms. A DNA-strain typing, using analysis of variable number tandem repeats and the direct repeats (VNTR/DR) of those isolates, was used to compare them to M. bovis isolates commonly found in New Zealand cattle and wildlife. In all cases of M. pinnipedii in cattle, only one animal in the herd was found to be infected. In six of seven cases, the lesions were in the thoracic lymph nodes, indicating a likely aerosol pathway. The lack of multiple cases within a herd suggests that cow-to-cow transmission is uncommon, if it occurs at all. There was no significant difference between case and control farms in distance to sea, herd size, herd type, or farming practice. The odds ratio for access to the beach for cattle on the Chatham Islands was significantly higher than it was for farms on the mainland coastal areas (odds ratio [OR]53.6, 95% CI51.1-11.4) Likewise, the odds ratio for acquiring tuberculosis was increased when farmers had seen seals on the property (OR5 9, 95% CI51.4-56.1 ). In all case farms, cattle had access to seals by beach grazing areas or waterways connecting directly with the ocean. The VNTR/DR typing of the isolates showed some variation in the M. pinnipedii isolates, with only two being identical; all isolates were easily distinguishable from M. bovis isolates.

Pinnipediae

“…Infection in free ranging pinnipeds is confined to the southern hemisphere and transmission between species is thought to be by sub-Antarctic fur seals whose range overlaps with eight other otariid species (Bastida et al, 1999). To date, mycobacteriosis due to M. pinnipedii has not been reported for any phocid species; however, the potential host range is broad and transmission from infected fur seals and sea lions has been described for zoo species, domestic cattle, and humans (Cousins et al, 2003;Kiers et al, 2008;Loeffler et al, 2014;Moser et al, 2008;Thompson et al, 1993;Thorel et al, 1998). The most likely route of infection is aspiration of aerosolized bacteria shed in respiratory secretions of infected pinnipeds.…”

The discovery, function and development of the variable number tandem repeats in differentMycobacteriumspecies

“…Recently, M. pinnipedii was isolated from beef cattle in New Zealand, and their genotypes were identified by 8 VNTR loci (including MIRU 40, ETR C, D and E, QUB 11a, 18, 26 and 3232). Only MIRU 40 showed no polymorphism among the tested strains (Loeffler et al, 2014).…”

Applying the One Health Concept to Mycobacterial Research – Overcoming Parochialism

“…Mycobacterium pinnipedii infection in marine mammals in Australia, New Zealand and South America as well as in camels, porcupines, llamas and humans has been reviewed in Rodriguez‐Campos et al., ; it is an occupational zoonosis (Jurczynski et al., ; Nugent and Cousins, ). Recently, this bacterium has been isolated from cattle in New Zealand (Loeffler et al., ), which increases its potential zoonotic risk through occupational exposure of farmers. Mycobacterium microti is a pathogen of small rodents, but it has been identified as a co‐infectious agent in immunocompromised patients in Europe (Cavanagh et al., ; Jenkins et al., ; Francis Xavier et al., ; Rüfenacht et al., ).…”