The use of rats to detect drug-resistant TB

Beyene, Negussie; Sitotaw, Alemu Lakew; Telila, E. G.; Gebre, Henok Alemu; Alemu, N. B.; Burny, Robert; Cox, Christophe; Soka, J.; Tegegn, B.; Wassie, L.; Bobosha, K.; Agizew, T.

doi:10.5588/pha.22.0059

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…As in cancer detection studies, the dogs were permitted to explore the wheel without the handler being present allowing for double-blind studies. The current study employed a 1-in-5 bioassay that replicated methods used by the Belgian Police in human scent line-ups [30] such that the same panel could be replicated multiple times with the samples in different positions [31]. In addition, more than three times the number of samples (n = 518; 120 CWD positive and 405 non-infected samples) were presented in the current study.…”

Section: Discussionmentioning

confidence: 99%

Biodetection of an odor signature in white-tailed deer associated with infection by chronic wasting disease prions

Golden,

Ramirez,

Stevens

et al. 2024

Preprint

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Chronic wasting disease (CWD) has become a major concern among those involved in managing wild and captive cervid populations. CWD is a fatal, highly transmissible spongiform encephalopathy caused by an abnormally folded protein, called a prion. Prions are present in a number of tissues, including feces and urine in CWD infected animals, suggesting multiple modes of transmission, including animal-to-animal, environmental, and by fomite. CWD management is complicated by the lack of practical, non-invasive, live-animal screening tests. We previously demonstrated that ferrets were able to detect and discriminate fecal samples from ducks infected or not infected with avian influenza virus based on odor. That work clearly predicted that animal biodetectors can be trained to identify populations and/or individuals infected with CWD via detection of fecal odors. Such a tool may also prove useful in identifying potentially infected live animals, carcasses, urine, feces, and contaminated environments. Toward this goal, dogs were trained to detect and discriminate CWD infected individuals from non-infected deer in a laboratory setting. Dogs were tested with novel panels of fecal samples demonstrating the dogs' ability to generalize a learned odor profile to novel odor samples based on infection status. Additionally, dogs were transitioned from alerting to fecal samples to an odor profile that consisted of CWD infection status with a different odor background using different sections of gastrointestinal tracts. These results indicated that canine biodetectors can discriminate the specific odors emitted from the feces of non-infected versus CWD infected white-tailed deer as well as generalizing the learned response to other tissues collected from infected individuals. These findings suggest that the health status of wild and farmed cervids can be evaluated non-invasively for CWD infection via monitoring of volatile metabolites thereby providing an effective tool for rapid CWD surveillance.

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Section: Discussionmentioning

confidence: 99%

Biodetection of an odor signature in white-tailed deer associated with infection by chronic wasting disease prions

Golden,

Ramirez,

Stevens

et al. 2024

Preprint

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Increased tuberculosis case detection in Tanzanian children and adults using African giant pouched rats

Agizew,

Soka,

Fast

et al. 2024

BMC Infect Dis

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Background African giant pouched rats, trained by Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling (APOPO), have demonstrated their ability to detect tuberculosis (TB) from sputum. We assessed rat-based case detection and compared the mycobacterium bacillary load (MTB-load) in children versus adults. Methods From January–December 2022, samples were collected prospectively from 69 Directly Observed Therapy (DOT) facilities’ presumed TB patients. Using an average of five rats, APOPO re-evaluated patients with bacteriologically negative (sputum-smear microscopy or Xpert MTB/RIF) results. Rat-positive samples were tested using concentrated smear light-emitting diode microscopy to confirm TB detection before treatment initiation. The rats’ identification of pulmonary TB is based on smelling TB-specific volatile organic compounds (VOCs) in sputum. Using STATA, Chi-square for odds ratio and confidence interval was calculated and evaluated: (1) the yield of rat-based TB detection compared to that of the health facilities; (2) rat-based TB detection in children versus adults; and (3) rats’ ability to detect TB across MTB-loads and between children and adults. Results From 35,766 patients, 5.3% (1900/35,766) were smear-positive and 94.7% (33,866/35,766) were smear or Xpert-negatives at DOTS facility. Of those with negative results, 2029 TB cases were detected using rats, contributing to 52% (2029/3929 of total TB identified), which otherwise would have been missed. Compared to DOT facilities, rats were six-fold more likely to detect TB among Acid Fast Bacilli (AFB) 1+/scanty [90% (1829/2029) versus 60% (1139/1900), odds ratio, OR = 6.11, 95% confidence interval, CI: 5.14–7.26]; twice more likely to identify TB cases among children [71% (91/129) versus 51% (1795/3542), OR = 2.3, 95% CI: 1.59–3.42]; and twice more likely to identify TB cases among children with AFB 1+/scanty than adults with the same MTB-load [5% (86/1703) versus 3% (28/1067), OR = 2.0, 95% CI: 1.28–3.03]. Conclusions Rats contributed over half of the TB cases identified in program settings, and children, especially those with a lower MTB-load, were more likely to be diagnosed with TB by rats. The chemical signatures, VOCs, were only available for adults, and further research describing the characteristics of VOCs in children versus adults may pave the way to enhance TB diagnosis in children.

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Biodetection of an odor signature in white-tailed deer associated with infection by chronic wasting disease prions

Golden,

Ramirez,

Stevens

et al. 2024

PLoS ONE

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Chronic wasting disease (CWD) has become a major concern among those involved in managing wild and captive cervid populations. CWD is a fatal, highly transmissible spongiform encephalopathy caused by an abnormally folded protein, called a prion. Prions are present in a number of tissues, including feces and urine in CWD infected animals, suggesting multiple modes of transmission, including animal-to-animal, environmental, and by fomite. CWD management is complicated by the lack of practical, non-invasive, live-animal screening tests. Recently, there has been a focus on how the volatile odors of feces and urine can be used to discriminate between infected and noninfected animals in several different species. Such a tool may prove useful in identifying potentially infected live animals, carcasses, urine, feces, and contaminated environments. Toward this goal, dogs were trained to detect and discriminate CWD infected individuals from non-infected deer in a laboratory setting. Dogs were tested with novel panels of fecal samples demonstrating the dogs’ ability to generalize a learned odor profile to novel odor samples based on infection status. Additionally, dogs were transitioned from alerting to fecal samples to an odor profile that consisted of CWD infection status with a different odor background using different sections of gastrointestinal tracts. These results indicated that canine biodetectors can discriminate the specific odors emitted from the feces of non-infected versus CWD infected white-tailed deer as well as generalizing the learned response to other tissues collected from infected individuals. These findings suggest that the health status of wild and farmed cervids can be evaluated non-invasively for CWD infection via monitoring of volatile metabolites thereby providing an effective tool for rapid CWD surveillance.

show abstract

The use of rats to detect drug-resistant TB

Cited by 3 publications

References 8 publications

Biodetection of an odor signature in white-tailed deer associated with infection by chronic wasting disease prions

Biodetection of an odor signature in white-tailed deer associated with infection by chronic wasting disease prions

Increased tuberculosis case detection in Tanzanian children and adults using African giant pouched rats

Biodetection of an odor signature in white-tailed deer associated with infection by chronic wasting disease prions

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