Putative transmission of Mycobacterium tuberculosis infection from a human to a dog

Review Canine Tuberculosis - An Emerging Concern

Canine mycobacterial disease was first recognised over 100 years ago but is now an emerging concern. All reported cases of tuberculous disease in dogs have been caused by infection with one of three Mycobacterium tuberculosis-complex (MTBC) organisms (M. tuberculosis, Mycobacterium bovis, and Mycobacterium microti). Molecular PCR and interferon-gamma release assays offer alternative or complementary diagnostic pathways to that of specialist culture, which is limited by availability, sensitivity, and the time it takes to get a result. Optimised triple antimicrobial protocols offer an excellent chance of a successful outcome in dogs where treatment can be considered and is attempted. In this review, the clinical presentation, diagnosis, treatment, and prognosis of canine tuberculosis are discussed.

No molecular evidence of SARS-CoV-2 infection in companion animals from Veracruz, Mexico

Active epidemiological surveillance of infectious agents represents a fundamental tool for understanding the transmission dynamics of pathogens and establishing public policies that can reduce or limit their expansion. Epidemiological surveillance of emerging agents, such as the recently recognized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of COVID-19, is essential to establish the risk of transmission between species. Recent studies reveal that companion animals are organisms susceptible to being infected by this pathogen due to the close contact they have with their owners. For this reason, the aim of the present work was to detect the presence of SARS-CoV-2 in dogs and cats in the state of Veracruz, Mexico, where there is active transmission of this microorganism in human populations. Oral and nasopharyngeal swab samples were collected from dogs and cats with a history of exposure to patients with COVID-19. Total RNA was extracted and detection of viral genes N1 and N2 was performed by reverse transcription polymerase chain reaction (RT-qPCR). All 130 samples of companion animals tested by RT-qPCR for SARS-CoV-2 were negative at the time they were collected. This study represents the second active surveillance of SARS-CoV-2 in populations of domestic dogs and cats in Latin America and the first approach in Mexico. Given that coronaviruses have shown a high capacity to be transmitted between species, it is imperative to establish measures to prevent this agent from entering and establishing in populations of companion animals.

Diversity of Mycobacterium tuberculosis Complex from Cattle Lymph Nodes in Eastern Cape Province

Tuberculosis (TB) remains a major health challenge in South Africa and the condition in humans has been well researched and documented. However, investigations on the circulating Mycobacterium tuberculosis complex (MTBC) strains from cattle in the Eastern Cape Province of South Africa are insufficient. This study delineated the diversity of MTBC isolates from cows' lymph nodes. A total of 162 MTBC isolates, collected over a one-year period from cattle lymph nodes from two abattoirs, were submitted to spoligotyping and 12 MIRU-VNTR typing. The spoligotyping results were matched with isolates in the universal spoligotyping database (SITVIT2). Our study identified 27 spoligotype patterns, with 10 shared types assigned to five lineages: the East-Asian (Beijing) was predominant, 17.9%, and East-Asian (Microti) and Latin-American-Mediterranean S were the least detected with 0.6%. Spoligotyping showed a higher clustering rate of 82.1%, with the lowest being the Hunter-Gaston Diversity Index (HGDI) of 0.485; 12 MIRU-VNTR resulted in a clustering rate of 64.8%, showing a higher HGDI of 0.671. The results of this study show a high diversity of MTBC strains in the Eastern Cape Province and clustering rate, which indicates ongoing transmission in the province.

An alert of Mycobacterium tuberculosis infection of rhesus macaques in a wild zoo in China

Mycobacterium tuberculosis, the pathogen that causes tuberculosis (TB), is becoming increasingly recognized as an important cause of fatal chronic illnesses in China. In this study, we report an infectious disease among 84 rhesus macaques at a Chinese zoo. Their clinical signs and symptoms were very similar with the manifestations of TB in humans. To determine the potential pathogens of this outbreak, many methods were used. First, tuberculin skin tests showed that none of the monkeys displayed significant skin reactions. Subsequently, the sera were tested for specific antibody IgG; 29 (34.5%) and 39 (46.4%) blood samples tested positive by TB-IgG and TB-DOT, respectively. Radiographic examination showed characteristic imageology changes in 14 (16.7%) monkeys. One individual determined as positive by the above three methods was euthanized, and histopathological analysis demonstrated typical granulomas and caseous necrosis in the lung, liver, spleen, and intestine. Furthermore, the pathogenic mycobacteria were isolated from lung lobe, cultured on acidic Lowenstein-Jensen culture medium, and identified as M. tuberculosis by real-time PCR and DNA sequencing. Nevertheless, the origin of the infection remained unknown. These findings emphasize the need to strengthen the management and training of staff, especially those working at animal shelters.

Emerging and Re-Emerging Zoonoses of Dogs and Cats

Simple Summary

Dogs and cats have been sharing our environment for a long time and as pets they bring major psychological well-being to our modern urbanized society. However, they still can be a source of human infection by various pathogens, including viruses, bacteria, parasites, and fungi.

Abstract

Since the middle of the 20th century, pets are more frequently considered as “family members” within households. However, cats and dogs still can be a source of human infection by various zoonotic pathogens. Among emerging or re-emerging zoonoses, viral diseases, such as rabies (mainly from dog pet trade or travel abroad), but also feline cowpox and newly recognized noroviruses or rotaviruses or influenza viruses can sicken our pets and be transmitted to humans. Bacterial zoonoses include bacteria transmitted by bites or scratches, such as pasteurellosis or cat scratch disease, leading to severe clinical manifestations in people because of their age or immune status and also because of our closeness, not to say intimacy, with our pets. Cutaneous contamination with methicillin-resistant Staphylococcus aureus, Leptospira spp., and/or aerosolization of bacteria causing tuberculosis or kennel cough are also emerging/re-emerging pathogens that can be transmitted by our pets, as well as gastro-intestinal pathogens such as Salmonella or Campylobacter. Parasitic and fungal pathogens, such as echinococcosis, leishmaniasis, onchocercosis, or sporotrichosis, are also re-emerging or emerging pet related zoonoses. Common sense and good personal and pet hygiene are the key elements to prevent such a risk of zoonotic infection.

Reverse zoonotic disease transmission (zooanthroponosis): a systematic review of seldom-documented human biological threats to animals

Background

Research regarding zoonotic diseases often focuses on infectious diseases animals have given to humans. However, an increasing number of reports indicate that humans are transmitting pathogens to animals. Recent examples include methicillin-resistant Staphylococcus aureus, influenza A virus, Cryptosporidium parvum, and Ascaris lumbricoides. The aim of this review was to provide an overview of published literature regarding reverse zoonoses and highlight the need for future work in this area.

Methods

An initial broad literature review yielded 4763 titles, of which 4704 were excluded as not meeting inclusion criteria. After careful screening, 56 articles (from 56 countries over three decades) with documented human-to-animal disease transmission were included in this report.

Findings

In these publications, 21 (38%) pathogens studied were bacterial, 16 (29%) were viral, 12 (21%) were parasitic, and 7 (13%) were fungal, other, or involved multiple pathogens. Effected animals included wildlife (n = 28, 50%), livestock (n = 24, 43%), companion animals (n = 13, 23%), and various other animals or animals not explicitly mentioned (n = 2, 4%). Published reports of reverse zoonoses transmission occurred in every continent except Antarctica therefore indicating a worldwide disease threat.

Interpretation

As we see a global increase in industrial animal production, the rapid movement of humans and animals, and the habitats of humans and wild animals intertwining with great complexity, the future promises more opportunities for humans to cause reverse zoonoses. Scientific research must be conducted in this area to provide a richer understanding of emerging and reemerging disease threats. As a result, multidisciplinary approaches such as One Health will be needed to mitigate these problems.

Transmission of Mycobacterium tuberculosis from an Asian elephant (Elephas maximus) to a chimpanzee (Pan troglodytes) and humans in an Australian zoo

Mycobacterium tuberculosis is primarily a pathogen of humans. Infections have been reported in animal species and it is emerging as a significant disease of elephants in the care of humans. With the close association between humans and animals, transmission can occur. In November 2010, a clinically healthy Asian elephant in an Australian zoo was found to be shedding M. tuberculosis; in September 2011, a sick chimpanzee at the same zoo was diagnosed with tuberculosis caused by an indistinguishable strain of M. tuberculosis. Investigations included staff and animal screening. Four staff had tuberculin skin test conversions associated with spending at least 10 hours within the elephant enclosure; none had disease. Six chimpanzees had suspected infection. A pathway of transmission between the animals could not be confirmed. Tuberculosis in an elephant can be transmissible to people in close contact and to other animals more remotely. The mechanism for transmission from elephants requires further investigation.

Mycobacterium microti infection in the cat: a case report, literature review and recent clinical experience

OVERVIEW

Mycobacterium microti infection is infrequently described in cats in the veterinary literature. It can be one of a large number of possible differential diagnoses in a feline patient with dermal nodules and non-healing draining ulcers, and can occasionally spread to involve the lungs and/or other areas of the body.

CASE SUMMARY

This report describes the clinical signs, eventual diagnosis and variable response to treatment in a cat in Switzerland with recurrent cutaneous M microti infection. Only after several diagnostic and therapeutic attempts, over more than 2 years, was the species of Mycobacterium finally identified and targeted therapy given.

PRACTICAL RELEVANCE

For any cat in which there is even a low suspicion of mycobacterial infection, the authors recommend that an aggressive diagnostic approach is taken. Tissue specimens should be collected and frozen early on, and, as soon as acid-fast bacilli are detected, samples should be sent to a mycobacterial reference laboratory for definitive identification.

LITERATURE REVIEW

A review of the literature relating to the aetiopathogenesis, diagnosis and management of M microti infection in cats and dogs is included. This is supplemented with clinical and therapeutic experience gained from this case and other, unpublished cases managed over the past 15 years by one of the authors (DGM).

Molecular characterization of Mycobacterium tuberculosis complex (MTBC) isolated from cattle in northeast and northwest China

We studied throat swabs and corresponding serum samples collected from 1067 protein purified derivative (PPD)-tuberculin skin test (TST) positive cattle from different regions of China. The 1067 throat swabs were inoculated onto modified Löwenstein-Jensen medium for the isolation and culture of Mycobacteria. Acid-fast bacilli were identified using traditional biochemical methods, polymerase chain reaction (PCR) amplification and multiplex PCR. They were distinguished as Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM) strains. An indirect Enzyme-Linked Immunosorbent Assay (ELISA) was applied to detect specific antibodies against bovine TB (bTB). Correlations among the ELISA, bacteriology and TST were analyzed and compared. Spoligotyping and variable number tandem repeats-mycobacterial interspersed repetitive unit (VNTR-MIRU) analysis were used to genotype the MTBC. In total, 111 strains of Mycobacteria were cultured from the 1067 throat swab samples, including 43 stains of MTBC (14 strains of Mycobacterium bovis and 29 of Mycobacterium tuberculosis) and 68 strains of NTM. Thirty-eight MTBC strains and four NTM strains were isolated from 72 throat swab samples that the ELISA determined were antibody positive; five MTBC strains and 64 NTM strains were isolated from 995 throat swab samples that were antibody negative on the ELISA. The positive isolation rates of MTBC and NTM were 38.7% (43/111) and 61.3% (68/111), respectively. The concordance rate of cultured MTBC with a positive result on the indirect ELISA for antibody was 52.8% (38/72), which was much higher than the positive rate for TST (4.0%; 43/1067). Genotyping of the 43 strains of MTBC isolated, using spoligotyping and VNTR-MIRU, showed that the 43 isolates had 26 genotypes; 16 strains had a unique genotype. Two groups of six strains and two strains, respectively, showed the same spoligotyping pattern, and belonged to the Beijing family and Beijing-like family, respectively. Combined application of spoligotyping and VNTR-MIRU typing would improve the molecular epidemiological investigation and monitoring of the etiology of bTB in China.

Infectious hepatopathies in dogs and cats

This article serves to review the various infectious diseases that affect the liver primarily or as a part of systemic infection. Although bacterial infections are probably the most common cause of infectious hepatitis, the clinician should be aware of other potential organisms and other commonly involved systems. Therefore, this article includes a description of common bacterial, mycobacterial, viral, fungal, protozoal, parasitic, and rickettsial diseases in dogs and cats.