Recognising the gross pathology of tuberculosis in South American camelids, deer, goats, pigs and sheep

Abstract

Tuberculosis (TB) can be difficult to recognise owing to its diverse pathology and similar gross pathology to other conditions. Early detection of TB outbreaks goes a long way to preventing further spread of the disease. This article describes the spectrum of possible gross pathology of TB in a range of non-bovine farmed species for which there is no routine antemortem surveillance. For these species, detection of the disease is dependent on gross pathology at slaughter or postmortem examination findings.

Zoonotic diseases in South American camelids in England and Wales

“…There is also some evidence from field epidemiological investigations undertaken by APHA to suggest that TB can additionally spread between SAC premises through the movement of undetected infected camelids. [17,18] There have been two documented cases of human M. bovis infection attributed to close and/or prolonged contact with tuberculous camelids in England. The first involved a veterinary surgeon in Devon who developed a cutaneous granuloma in her thumb a few weeks after treating, euthanasing and conducting a postmortem examination on an infected alpaca with extensive TB pathology in the thorax.…”

“…Nearly all of those cases occurred in areas where TB is endemic in cattle and badgers, and it is possible that cases in SACs reflect infection spillover from those true reservoir species. There is also some evidence from field epidemiological investigations undertaken by APHA to suggest that TB can additionally spread between SAC premises through the movement of undetected infected camelids [17, 18].…”

A proof of concept study to assess the potential of PCR testing to detect natural Mycobacterium bovis infection in South American camelids

“…A faeces sample was taken from the rectum immediately on opening the carcass using clean gloves and instruments to minimise contamination. For each of the SACs sampled any pathology typical of M. bovis infection [ 5 ] was recorded in the post mortem report by the pathologists.…”

“…In some herds disease has spread widely before detection, and losses in these herds can be very high. On post-mortem examination the characteristic gross pathology of TB in SACs can be extensive [ 5 ] suggesting that M. bovis may be present in nasal discharge, blood or faeces. While this could be a source for onwards spread of infection it could also facilitate ante mortem detection of disease.…”

TB or not TB?

“…In GB, tuberculosis (TB) in animals is not confined to cattle and badger; it is also a serious concern in deer, South American camelids (Crawshaw et al . ) and cats (Gunn‐Moore et al . ).…”