Social network analysis and whole-genome sequencing to evaluate disease transmission in a large, dynamic population: A study of avian mycobacteriosis in zoo birds

This study combined a social network analysis and whole-genome sequencing (WGS) to test for general patterns of contagious spread of a mycobacterial infection for which pathways of disease acquisition are not well understood. Our population included 275 cases diagnosed with avian mycobacteriosis that were nested in a source population of 16,430 birds at San Diego Zoo Wildlife Alliance facilities from 1992 through mid-2014. Mycobacteria species were determined using conventional methods and whole genome sequencing (WGS). Mycobacterium avium avium (MAA) and Mycobacterium genavense were the most common species of mycobacteria identified and were present in different proportions across bird taxa. A social network for the birds was constructed from the source population to identify directly and indirectly connected cases during time periods relevant to disease transmission. Associations between network connectivity and genetic similarity of mycobacteria (as determined by clusters of genotypes separated by few single nucleotide polymorphisms, or SNPs) were then evaluated in observed and randomly generated network permutations. Findings showed that some genotypes clustered along pathways of bird connectivity, while others were dispersed throughout the network. The proportion of directly connected birds having a similar mycobacterial genotype was 0.36 and significant (p<0.05). This proportion was higher (0.58) and significant for MAA but not for M. genavense. Evaluations of SNP distributions also showed genotypes of MAA were more related in connected birds than expected by chance; however, no significant patterns of genetic relatedness were identified for M. genavense, although data were sparse. Integrating the WGS analysis of mycobacteria with a social network analysis of their host birds revealed significant genetic clustering along pathways of connectivity, namely for MAA. These findings are consistent with a contagious process occurring in some, but not all, case clusters.

Risk Management in the New Frontier of Professional Liability for Nosocomial Infection: Review of the Literature on Mycobacterium Chimaera

Background: Mycobacterium chimaera (MC) is of recent origin and belongs to the large family of non-tuberculous mycobacteria. In recent years, it has shown a high infectious capacity via the aerosol produced by operating room equipment, such as heater–cooler units (HCU). The infection has a long latent period and high mortality rate. Genetic and epidemiological studies have shown that there is a clear link between the infection and a specific HCU model manufactured by LivaNova/Sorin. There is, therefore, a strong possibility that contamination occurs during device construction. The objective of this article is to describe the characteristics of this particular infection in view of the medico–legal implications on professional liability, specifically focusing on current evidence regarding contamination prevention. Methods: we have analyzed the clinical characteristics and data from the autopsic investigations performed on a patient who died as a result of MC infection, in addition to analyzing all pertinent recommendation documents available internationally. We searched for all articles in the literature available on MEDLINE between 1995 and 30 July 2020, using the search words “Mycobacterium chimaera”. We then analyzed those articles and reported only those that provide useful information regarding prevention techniques for containing dissemination and contamination. Results: the literature review produced 169 results that highlight the need to develop systems to mitigate and eliminate the risk of MC infection in operating rooms such as physical containment measures, e.g. device replacement, use of safe water, providing patients with information, and training healthcare professionals. Conclusions: from a medico–legal viewpoint, this particular situation represents a new frontier of professional liability, which includes manufacturers of electromedical equipment. In order to comprehend the true extent of this silent global epidemic, the development of an organic, preventative monitoring system is essential.

Spatiotemporal network structure among "friends of friends" reveals contagious disease process

Disease transmission can be identified in a social network from the structural patterns of contact. However, it is difficult to separate contagious processes from those driven by homophily, and multiple pathways of transmission or inexact information on the timing of infection can obscure the detection of true transmission events. Here, we analyze the dynamic social network of a large, and near-complete population of 16,430 zoo birds tracked daily over 22 years to test a novel “friends-of-friends” strategy for detecting contagion in a social network. The results show that cases of avian mycobacteriosis were significantly clustered among pairs of birds that had been in direct contact. However, since these clusters might result due to correlated traits or a shared environment, we also analyzed pairs of birds that had never been in direct contact but were indirectly connected in the network via other birds. The disease was also significantly clustered among these friends of friends and a reverse-time placebo test shows that homophily could not be causing the clustering. These results provide empirical evidence that at least some avian mycobacteriosis infections are transmitted between birds, and provide new methods for detecting contagious processes in large-scale global network structures with indirect contacts, even when transmission pathways, timing of cases, or etiologic agents are unknown.

Global Health Estimate of Invasive Mycobacterium chimaera Infections Associated with Heater-Cooler Devices in Cardiac Surgery

Investigations of a worldwide epidemic of invasive Mycobacterium chimaera associated with heater-cooler devices in cardiac surgery have been hampered by low clinical awareness and challenging diagnoses. Using data from Switzerland, we estimated the burden of invasive M. chimaera to be 156-282 cases/year in 10 major cardiac valve replacement market countries.

Study suggests hidden epidemic in CF patients

Dangerous Mycobacterium strains appear to be spreading.

Paramecium caudatum enhances transmission and infectivity of Mycobacterium marinum and M. chelonae in zebrafish Danio rerio

Mycobacterial infections in laboratory zebrafish Danio rerio are common and widespread in research colonies. Mycobacteria within free-living amoebae have been shown to be transmission vectors for mycobacteriosis. Paramecium caudatum are commonly used as a first food for zebrafish, and we investigated this ciliate's potential to serve as a vector of Mycobacterium marinum and M. chelonae. The ability of live P. caudatum to transmit these mycobacteria to larval, juvenile and adult zebrafish was evaluated. Infections were defined by histologic observation of granulomas containing acid-fast bacteria in extraintestinal locations. In both experiments, fish fed paramecia containing mycobacteria became infected at a higher incidence than controls. Larvae (exposed at 4 d post hatch) fed paramecia with M. marinum exhibited an incidence of 30% (24/80) and juveniles (exposed at 21 d post hatch) showed 31% incidence (14/45). Adult fish fed a gelatin food matrix containing mycobacteria within paramecia or mycobacteria alone for 2 wk resulted in infections when examined 8 wk after exposure as follows: M. marinum OSU 214 47% (21/45), M. marinum CH 47% (9/19), and M. chelonae 38% (5/13). In contrast, fish feed mycobacteria alone in this diet did not become infected, except for 2 fish (5%) in the M. marinum OSU 214 low-dose group. These results demonstrate that P. caudatum can act as a vector for mycobacteria. This provides a useful animal model for evaluation of natural mycobacterial infections and demonstrates the possibility of mycobacterial transmission in zebrafish facilities via contaminated paramecia cultures.

Direction of association between bite wounds and Mycobacterium bovis infection in badgers: implications for transmission

Background

Badgers are involved in the transmission to cattle of bovine tuberculosis (TB), a serious problem for the UK farming industry. Cross-sectional studies have shown an association between bite wounds and TB infection in badgers which may have implications for M. bovis transmission and control, although the sequence of these two events is unclear. Transmission during aggressive encounters could potentially reduce the effectiveness of policies which increase the average range of a badger and thus its opportunities for interaction with other social groups.

Methods

Data were obtained on badgers captured during a long term study at Woodchester Park, UK (1998–2006). Many badgers had multiple observations. At each observation, the badger was assigned a “state” depending on presence of bite wounds and/or TB infection. Hence each badger had a “transition” from the previous state to the current state. We calculated the numbers of each type of transition and the time spent in each state. Transition rates were calculated for each transition category, dividing the number of such transitions by the total time at risk. We compared the rate of bite wound acquisition in infected badgers with that for uninfected badgers and the rate of positive M.bovis test results in bitten badgers with that in unbitten badgers.

Results

The rate of bite wound acquisition in infected badgers (0.291 per year) was 2.09 (95% CI: 1.41, 3.08) times that in uninfected badgers (0.139 per year). The rate of positive M.bovis test results in bitten badgers (0.097 per year) was 2.45 (95% CI: 1.29, 4.65) times that in unbitten badgers (0.040 per year).

Conclusions

We found strong evidence of both potential sequences of events consistent with transmission via bite wounds and distinctive behaviour in infected badgers. The complex relationship between behaviour and infection must be considered when planning TB control strategies.

Mycobacterial infection in the ferret

Mycobacteriosis is an important disease in the feral ferret (Mustela putorius furo) of New Zealand; elsewhere, reports of tuberculosis in the ferret are sporadic. Genus Mycobacterium consists of aerobic, non-spore-forming, gram-positive, nonmotile bacteria that characteristically feature a cell wall rich in mycolic acids and esters. The epidemiology of mycobacteriosis in the ferrets of New Zealand involves complex interactions between ferrets, possums, and livestock. Investigators have shown that the ferret is highly susceptible only to Mycobacterium bovis infection and is more resistant to infection by other Mycobacterium spp. The principal site of all mycobacterial infection in the ferret is the gastrointestinal tract.

Mycobacterial infections in reptiles

Mycobacteriosis is an important disease worldwide. Although commonly associated with higher vertebrates, including humans, it has been reported in only a handful of reptile cases. The purpose of this article is to review the literature as it relates to mycobacteriosis in reptiles. Knowledge of the epidemiology of this disease can be useful to veterinarians working with these animals, especially when working on a diagnosis and making recommendations to clients regarding the need for case follow-up to rule in or rule out the potential presence of these pathogens in pet reptiles and best handling practices to minimize their exposure.

Mycobacteriosis in the rabbit and rodent

Spontaneous mycobacteriosis is rare in rabbits and rodents with the exception of the pygmy rabbit, and there are only a handful of reported cases involving other rodents. Mycobacterium avium complex was the most commonly identified organism in reports of spontaneous mycobacteriosis involving rabbits and rodents. The resistance of rabbits and rodents to mycobacterial disease has been useful in understanding the disease in humans and other animals. Preventing or controlling Mycobacterium sp transmission from wildlife to domestic animals will require collaboration between agriculture, wildlife, environmental, and political entities. Understanding the ecology and epidemiology of mycobacteria is needed for better worldwide management of tuberculosis.

Pathology of mycobacteriosis in birds

Avian mycobacteriosis is a disease that affects companion, captive exotic, wild, and domestic birds. The disease in birds is generally caused by Mycobacterium avium subsp avium but more than 10 other species of mycobacteria infect birds. Oral route of infection appears to be the primary mode of transmission. In some cases, the extensive involvement of the respiratory system suggests an airborne mode of transmission. Molecular diagnostic techniques have improved the ability to confirm the disease. Avian mycobacteriosis is an important veterinary and economic risk in birds and mammals. Exposure of humans to infected birds may cause a zoonotic infection.

Amphibian mycobacteriosis

Amphibians are commonly kept in laboratory and zoological facilities and are becoming more frequent as pets. However, many amphibian species are declining in the wild owing to a variety of infectious and noninfectious diseases. This article reviews the current state of knowledge of mycobacteriosis in amphibian species, including pathogenesis, clinical signs, appropriate diagnostics, treatment options, and zoonotic potential and prevention. It is hoped this review will provide clinical veterinarians and scientists the tools they need to provide better care for amphibian species suffering mycobacteriosis, as well as serve to stimulate additional research into amphibians affected by mycobacterosis.

Mycobacterial lesions in fish, amphibians, reptiles, rodents, lagomorphs, and ferrets with reference to animal models

Mycobacteriosis is a serious disease across many animal species. Approximately more than 120 species are currently recognized in the genus Mycobacterium. This article describes the zoonotic potential of mycobacteria and mycobacteriosis in fish, amphibians, rodents, rabbits, and ferrets. It considers clinical signs; histology; molecular methods of identification, such as polymerase chain reaction and DNA sequencing; routes of infection; and disease progression. Studying the disease in animals may aid in understanding the pathogenesis of mycobacterial infections in humans and identify better therapy and preventative options such as vaccines.

A review of mycobacteriosis in marine fish

Mycobacteriosis is a serious and often lethal disease of fish, affecting a wide range of species globally both in culture and wild settings. Caused by several species of the genus Mycobacterium, the disease has received considerable attention in recent years because of the discovery of new species in piscine hosts, epizootics in wild fisheries, and the ability of a few species to infect humans. The impact of this disease in aquaculture and the aquaria trade has been well reported and there is currently no widely accepted cure other than depopulation and facility disinfection. However, the impact on wild fisheries is poorly understood and may relate to species-specific interactions (host-pathogen) and possibly environmental stressors. In this review, much of what is known about mycobacteriosis in marine fish is summarized with particular attention to an epizootic in striped bass, Morone saxatilis, (Walbaum), in Chesapeake Bay, USA.

Transmission of Mycobacterium pinnipedii to humans in a zoo with marine mammals

OBJECTIVES

An outbreak of tuberculosis (TB) in sea lions occurred recently in a zoo in the Netherlands. The disease was detected in a captive colony consisting of 29 animals kept in an open air basin with an indoor night house. Approximately 25 animal keepers were in close contact with the animals.

METHODS

The sea lions were investigated using the tuberculin skin test (TST) with avian and bovine purified protein derivative (PPD) and, in case of positivity, necropsied. A survey was conducted among the animal keepers including TSTs with Mycobacterium tuberculosis complex PPD tuberculin, a chest X-ray and an interferon-gamma release assay (IGRA).

RESULTS

Necropsy was positive for TB in 13 of the 29 sea lions. Three cases of pulmonary involvement were found. Only one of these was infectious and it was therefore regarded as the source case. The causative mycobacterium was identified as M. pinnipedii. Six of the 25 animal keepers were TST-positive; in five of these, infection was confirmed by a positive IGRA.

CONCLUSION

Transmission of M. pinnipedii infection from sea lions to humans was established by TST. IGRA results largely agreed with the TST results. Nebulisation when cleaning the sea lions' enclosure was most likely the main cause of transmission to humans.

Mycobacterium pinnipedii: transmission from South American sea lion (Otaria byronia) to Bactrian camel (Camelus bactrianus bactrianus) and Malayan tapirs (Tapirus indicus)

Tuberculosis infections caused by Mycobacterium (M.) pinnipedii in a South American sea lion, Bactrian camel, and Malayan tapirs kept in two zoological gardens spanning a time period of 5 years are reported. The zoos were linked by the transfer of one tapir. Conventional bacteriological and molecular methods were applied to detect the pathogen. Spoligotyping and MIRU/VNTR-typing performed to assess the genetic similarity revealed identical molecular characteristics of the isolates from all animals involved. Anti-tuberculosis antibodies were detected using ELISA and a recently developed serological rapid test. The study shows that: (i) using molecular methods, the assessment of the genetic relationship of infectious agents helps to confirm the routes of infection, and that (ii) immunological tests may help to detect tuberculosis infections ante mortem more reliably and early. This would prevent the transfer of tuberculosis by asymptomatic animals.

Outbreak of tuberculosis caused by Mycobacterium caprae in a zoological garden

In the autumn of 2004, tuberculosis caused by Mycobacterium caprae occurred in a zoo in Slovenia. A dromedary camel (Camelus dromedarius) was killed after a history of progressive emaciation. Necropsy findings indicated disseminated tuberculosis, which was confirmed by cultivation of M. caprae. Consequently, a tuberculin skin test was performed in all epidemiologically linked animals and another dromedary camel and six bison (Bison bison) were positive and killed. Mycobacterium caprae was isolated from two bison while M. scrofulaceum and Mycobacterium spp. were found in two other bison, respectively. The second dromedary camel was found to be negative for mycobacteria under both microscopic and culture tests. The isolates were investigated with commercial identification kits, IS6110 PCR, IS6110 restriction fragment length polymorphism analysis, spoligotyping and mycobacterial interspersed repetitive units typing. Genotyping results revealed that the dromedary camel and the two bison were infected by the same M. caprae.

Isolation of Mycobacterium avium subspecies paratuberculosis from non-ruminant wildlife living in the sheds and on the pastures of Greek sheep and goats

This study aimed to: (1) investigate whether non-ruminant wildlife interfacing with dairy sheep and goats of four Greek flocks endemically infected with Mycobacterium avium subspecies paratuberculosis (MAP) harboured MAP and (2) genetically compare the strains isolated from the wildlife to those isolated from the small ruminants of these flocks. We cultured and screened, by polymerase chain reaction (PCR), pooled-tissue samples from 327 wild animals of 11 species for the MAP-specific IS900 insertion sequence. We also cultured faecal samples from 100 sheep or goats from each of the four flocks. MAP was detected in samples from 11 sheep, 12 goats, two mice, two rats, a hare and a fox. Only one rat had histopathological findings. Genetic typing categorized 21 isolates as cattle-type strains and two, from a house mouse and a goat respectively, as sheep-type strains; this is the first report of a rodent harbouring a sheep-type strain. The MAP types that were most frequently isolated amongst the sheep and goats of each flock were also the ones isolated from sympatric rodents; those isolated from the fox and hare also belonged to the predominant ruminant strains.

Isolation and identification of Mycobacteria from raw milk samples in Afyonkarahisar district of Turkey

Nontuberculous mycobacteria (NTM) have become a significant cause of infection with the emergence of HIV/AIDS, primarily Mycobacterium avium complex members, and NTM transmitted to humans from the environment (water, fruit, vegetables, beef, and milk). The objectives of this study were to show the presence of mycobacteria in milk and to determine their role as possible sources of human infection. For this, raw milk samples (N=35) were decontaminated with sodium dodecyl (lauryl) sulfate (SDS)-NaOH and inoculated on to Löwenstein-Jensen medium. After confirming positive 15 slides, isolated from milk by Ziehl-Neelsen technique, they were identified by PCR-Restriction Fragment Length Polymorphism Analysis (PRA). Nine hospital isolates which were identified as Mycobacterium tuberculosis complex by BACTEC were used at control group. We have detected Mycobacterium terrae, Mycobacterium kansassii, Mycobacterium agri at the end of the identification. Two mycobacterial raw milk isolates were not able to be identified by PRA. PRA patterns' were found to be similar to those which obtained University Faculty of Medical by BACTEC. The results showed that raw milk is to be possible sources for human infection. That is why UHF sterilized milk should be consumed.

Survival of environmental mycobacteria in Acanthamoeba polyphaga

Free-living amoebae in water are hosts to many bacterial species living in such an environment. Such an association enables bacteria to select virulence factors and survive in adverse conditions. Waterborne mycobacteria (WBM) are important sources of community- and hospital-acquired outbreaks of nontuberculosis mycobacterial infections. However, the interactions between WBM and free-living amoebae in water have been demonstrated for only few Mycobacterium spp. We investigated the ability of a number (n = 26) of Mycobacterium spp. to survive in the trophozoites and cysts of Acanthamoeba polyphaga. All the species tested entered the trophozoites of A. polyphaga and survived at this location over a period of 5 days. Moreover, all Mycobacterium spp. survived inside cysts for a period of 15 days. Intracellular Mycobacterium spp. within amoeba cysts survived when exposed to free chlorine (15 mg/liter) for 24 h. These data document the interactions between free-living amoebae and the majority of waterborne Mycobacterium spp. Further studies are required to examine the effects of various germicidal agents on the survival of WBM in an aquatic environment.

Mycobacterium gastri causing disseminated infection in children of same family

Two children of the same family were admitted to the pediatric ward with a history of productive cough, nocturnal sweats, and weight loss. On physical examination, lymphadenopathy was seen on both sides of the neck and axillae. The sizes of the lymph nodes varied, and some showed fistula formation with drainage. A chest x-ray of the boy revealed diffuse nodular densities, while in the girl, peribronchial thickening in both lower lung zones and hilar adenopathy were detected. Sonography of the abdomen and pelvis in both cases showed multiple para-aortic adenopathies with hypodense centers. Microscopic examination of sputum, gastric washings, and node biopsy specimens proved positive for acid-fast bacilli. Systematic identification of acid-fast bacilli on Lowenstein-Jensen culture media identified the isolates as Mycobacterium gastri. These appear to be the first cases of pediatric infection and the fourth report of human infection caused by this atypical Mycobacterium.

[Paratuberculosis in cattle. Reflections on the interactions with Crohn disease in humans. A literature review]

Based on more than 30 literature references, the author tries to explain the phenomena of paratuberculosis in cattle. He gives a short description of the origin of the infection, the disease categories, the diagnostic problems and eradication. Also the human infection with the Mycobacterium known as Mycobacterium avium supspecies paratuberculosis (MAP)--a recognized pathogen in animals causing some or possibly all cases of Crohn's disease will be discussed. The conclusion is that until now no study gives evidence that MAP may be transmitted to humans through foods derived from cattle with MAP infection.

Mycobacterium goodii infections associated with surgical implants at Colorado hospital

From February to October 2003, Mycobacterium goodii wound infections were identified among three patients who received surgical implants at a Colorado hospital. This report summarizes the investigation of the first reported nosocomial outbreak of M. goodii. Increased awareness is needed about the potential for nontuberculous mycobacteria to cause postoperative wound infections.

Two decades of disseminated tuberculosis at a university medical center: the expanding role of mycobacterial blood culture

We describe the clinical presentation, predisposing conditions, diagnostic approach, and outcome for 52 patients with disseminated tuberculosis who presented at Duke University Medical Center (Durham, NC) from 1980 through 1999. The mean age of the patients was 52 years (range, 2-93 years). Fever and weight loss were common at presentation, and delays in the initiation of therapy often occurred. Predisposing conditions included human immunodeficiency virus infection (46% of patients), immunosuppressive therapy (21%), alcoholism (12%), diabetes mellitus (12%), and hematologic disorders (8%); 17% of patients had no disorder of immunity detected. Examination of biopsy specimens from sites of localized disease, especially lymph nodes, had a high diagnostic yield. In this study, mycobacterial blood culture appeared to be as sensitive as bone marrow culture in diagnosing disseminated tuberculosis (sensitivity, 58% vs. 54%). To diagnose disseminated tuberculosis, a search for sites of localized disease should be undertaken, and samples from these sites should be obtained. Mycobacterial blood culture can play an increasing role in the diagnosis of disseminated tuberculosis when localized disease is not found.

Mycobacterial aerosols and respiratory disease

Environmental opportunistic mycobacteria, including Mycobacterium avium, M. terrae, and the new species M. immunogenum, have been implicated in outbreaks of hypersensitivity pneumonitis or respiratory problems in a wide variety of settings. One common feature of the outbreaks has been exposure to aerosols. Aerosols have been generated from metalworking fluid during machining and grinding operations as well as from indoor swimming pools, hot tubs, and water-damaged buildings. Environmental opportunistic mycobacteria are present in drinking water, resistant to disinfection, able to provoke inflammatory reactions, and readily aerosolized. In all outbreaks, the water sources of the aerosols were disinfected. Disinfection may select for the predominance and growth of mycobacteria. Therefore, mycobacteria may be responsible, in part, for many outbreaks of hypersensitivity pneumonitis and other respiratory problems in the workplace and home.

Risk factors for tuberculosis infection in children in contact with infectious tuberculosis cases in the Gambia, West Africa

OBJECTIVE

Tuberculosis (TB) infection is highly prevalent in developing countries. As infected children represent a large proportion of the pool from which TB cases will arise, knowledge of the factors that influence TB infection in children are of importance to evaluate transmission of infection in the community and adapt TB control activities. There are limited data on the risk of infection in child populations in developing countries.

METHODS

We performed a household contact study in The Gambia (West Africa), in which children who were living in contact with individuals who had proven smear-positive pulmonary TB cases were investigated. A questionnaire was addressed to the mother or caregiver of the child to investigate the presence of various risk factors and assess the degree of exposure of the child to the individual with TB within the household. A tuberculin skin test (TST) was performed on each child. TST sizes > or =5 and 10 mm, respectively, were considered positive.

RESULTS

Households of 206 TB cases were visited, and 384 children aged <5 years were examined. The median age was 2, and 48% were girls. The distribution of TST responses followed a bimodal pattern, with 135 (35%) children presenting a palpable induration. Random effects logistic regression analysis demonstrated that the risk of positive TST response in the child increased with the geographic proximity of the child to the individual with TB within the household and with the degree of activities shared with the individual with TB. It was also associated with the clinical severity of the disease in the index case. Nutritional status and presence of a bacille Calmette-Guérin (BCG) scar were not independent risk factors for TST positivity in this population. On multivariate analysis, the effect of geographic proximity to the individual with TB, household size, and duration of cough in the index case persisted for TST responses > or =5 mm.

CONCLUSIONS

In a highly endemic country with high BCG vaccination coverage in Africa, TB infection in children who were in contact with individual with infectious TB was directly related to the intensity of exposure of the child to the individual with TB. Our data suggest that a positive TST in a child reflects most probably TB infection rather than previous BCG vaccination. Contact tracing can play a major role in the control of TB in developing countries.

Experimental inoculation of pigeons (Columba livia) with Mycobacterium bovis

The purpose of this pilot study was to determine if pigeons (Columba livia) are susceptible to infection with Mycobacterium bovis by either oral or intratracheal inoculation and to assess their possible role in the lateral transmission of bovine tuberculosis. Six pigeons were orally inoculated with 1.3 x 10(5) colony-forming units of M. bovis, six pigeons were intratracheally inoculated with the same dose, and six pigeons served as noninoculated controls. The study continued for 90 days postinoculation (PI), with groups of birds necropsied at 30-day intervals, and fecal samples and tissues were collected for mycobacterial culture. Two pigeons, one intratracheally inoculated and one orally inoculated, shed M. bovis in their feces at 1 day PI, and one intratracheally inoculated bird shed M. bovis in its feces 60 days PI. Whereas no illness or weight loss was present during the course of the study, 2 of 12 inoculated birds exhibited microscopic lesions of mycobacteriosis, and the organism was isolated from tissues of three inoculated birds. Pigeons are susceptible to infection with M. bovis after high dose inoculation and can shed the organism in their feces for up to 60 days PI; intratracheally inoculated birds appear more likely to become active fecal shedders of M. bovis. Although these were high dose inoculations under experimental conditions, pigeons may potentially play a role in the lateral transmission of bovine tuberculosis between infected and uninfected mammalian hosts.

Infection of red deer, cattle, and humans with Mycobacterium bovis subsp. caprae in western Austria

Twelve cases of Mycobacterium bovis subsp. caprae infection have occurred in four humans, three cattle, and five red deer in western Austria since 1994. DNA-fingerprinting of the isolates suggested transmission in and between these species over several years. Contact with cattle, but not with goats, was found to be associated with three of four human cases.

An outbreak of mycobacterial furunculosis associated with footbaths at a nail salon

BACKGROUND

In September 2000, a physician in northern California described four patients with persistent, culture-negative boils on the lower extremities. The patients had received pedicures at the same nail salon. We identified and investigated an outbreak of Mycobacterium fortuitum furunculosis among customers of this nail salon.

METHODS

Patients were defined as salon customers with persistent skin infections below the knee. A case-control study was conducted that included the first 48 patients identified, and 56 unaffected friends and family members who had had a pedicure at the same salon served as controls. Selected M. fortuitum isolates, cultured from patients and the salon environment, were compared by pulsed-field gel electrophoresis.

RESULTS

We identified 110 customers of the nail salon who had furunculosis. Cultures from 34 were positive for rapidly growing mycobacteria (32 M. fortuitum and 2 unidentified). Most of the affected patients had more than 1 boil (median, 2; range, 1 to 37). All patients and controls had had whirlpool footbaths. Shaving the legs with a razor before pedicure was a risk factor for infection (70 percent of patients vs. 31 percent of controls; adjusted odds ratio, 4.8; 95 percent confidence interval, 2.1 to 11.1). Cultures from all 10 footbaths at the salon yielded M. fortuitum. The M. fortuitum isolates from three footbaths and 14 patients were indistinguishable by electrophoresis.

CONCLUSIONS

We identified a large outbreak of rapidly growing mycobacterial infections among persons who had had footbaths and pedicures at one nail salon. Physicians should suspect this cause in patients with persistent furunculosis after exposure to whirlpool footbaths.

Diptera as vectors of mycobacterial infections in cattle and pigs

Mycobacteria were isolated from 14 (4.5%) of 314 samples, containing 7791 adult Diptera, which were collected in the Czech Republic and Slovakia in 1997-2000. These flies were collected from three cattle herds with paratuberculosis, two pig herds with mycobacterial infections and one farm that kept both cattle and pigs and that did not have problems of mycobacterial infections. Mycobacterium intracellulare was isolated from Eristalis tenax Linnaeus (Diptera: Syrphidae) captured from a pig herd. Mycobacterium avium ssp. avium (serotype 8) was isolated from flies of the genera Drosophila Fallen (Diptera: Drosophilidae) and Musca Linnaeus (Diptera: Muscidae) originating from a pig herd. Mycobacterium spp. were isolated from Musca spp. and Mycobacterium fortuitum was isolated from dung flies of the genus Scatophaga Meigen (Diptera: Scatophagidae), Musca spp. and Stomoxys calcitrans Linnaeus (Diptera: Muscidae) captured in the same herd. Mycobacterium scrofulaceum was isolated from S. calcitrans from the farm with both cattle and pigs. Mycobacterium avium ssp. paratuberculosis was isolated from Scatophaga spp. collected from pastures grazed by one of the cattle herds and from Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) and Lucilia caesar Linnaeus (Diptera: Calliphoridae) captured in a slaughterhouse, where cattle infected with paratuberculosis were slaughtered. Mycobacterium phlei was isolated from flies of the genus Lucilia captured at a waste bin. These data indicate that mycobacteria may be spread by adult flies that have been in contact with material contaminated with these pathogens.

Causation of Crohn's disease by Mycobacterium avium subspecies paratuberculosis

Mycobacterium avium subspecies paratuberculosis (MAP) is a member of the M avium complex (MAC). It differs genetically from other MAC in having 14 to 18 copies of IS900 and a single cassette of DNA involved in the biosynthesis of surface carbohydrate. Unlike other MAC, MAP is a specific cause of chronic inflammation of the intestine in many animal species, including primates. The disease ranges from pluribacillary to paucimicrobial, with chronic granulomatous inflammation like leprosy in humans. MAP infection can persist for years without causing clinical disease. The herd prevalence of MAP infection in Western Europe and North America is reported in the range 21% to 54%. These subclinically infected animals shed MAP in their milk and onto pastures. MAP is more robust than tuberculosis, and the risk that is conveyed to human populations in retail milk and in domestic water supplies is high. MAP is harboured in the ileocolonic mucosa of a proportion of normal people and can be detected in a high proportion of full thickness samples of inflamed Crohn's disease gut by improved culture systems and IS900 polymerase chain reaction if the correct methods are used. MAP in Crohn's disease is present in a protease-resistant nonbacillary form, can evade immune recognition and probably causes an immune dysregulation. As with other MAC, MAP is resistant to most standard antituberculous drugs. Treatment of Crohn's disease with combinations of drugs more active against MAC such as rifabutin and clarithromycin can bring about a profound improvement and, in a few cases, apparent disease eradication. New drugs as well as effective MAP vaccines for animals and humans are needed. The problems caused by MAP constitute a public health issue of tragic proportions for which a range of remedial measures are urgently needed.

[The prevalence of salmonella, yersinia and mycobacteria in slaughtered pigs in Switzerland]

Clinically healthy food animals can be reservoirs for various foodborne pathogens. In general, such animals do not have lesions that are visible during meat inspection. Pigs are considered to be carriers of salmonella, yersinia and mycobacteria, but the risk of transmission to humans is difficult to assess. The aim of this study was to estimate the actual prevalence of the three above mentioned pathogens in the Swiss pig population and to comment on their significance. A total of 570 samples each of tonsils and mesenteric lymphnodes, were collected at two slaughterhouses from carcasses of apparently healthy pigs and analyzed for the presence of salmonella, yersinia and mycobacteria. The prevalence of salmonella (0.9%) was found to be lower than--while that of yersinia (8.1%) and mycobacteria (12.8%) about equal to--results reported from other European countries. Yersinia typing showed that serotype O:9 of Yersinia enterocolitica (2.5%) was 6 to 7 times more frequent than serotype O:3 (0.4%)--formerly the most frequent serotype. Mycobacterium avium was the most frequent isolate (90.7%) among the mycobacteria isolated. Although all three pathogens are present in the Swiss pig population, we consider the risk of transmission to humans via consumption of pork as low. Appropriate preventive measures and quality management should contribute to keep the risk under control.

Infectious complications of tattoos

Tattooing carries several medical risks, including the transmission of infectious diseases. We review the published literature on the transmission of hepatitis B virus, human immunodeficiency virus, Treponema pallidum, papillomavirus, Mycobacterium tuberculosis, and other organisms by tattooing. Education, through public health measures, should promote the prevention of infectious disease transmission. Particular populations who could benefit from education include prisoners, individuals involved with correctional facilities, youths, military personnel, and health care providers coming in contact with populations at risk for tattoos.

A tuberculosis outbreak from a patient's draining lesion: how did it happen?

1. Mycobacterium tuberculosis can be transmitted from a pulmonary source when droplet nuclei in the 1 to 5 micron range are generated by coughing, singing, or even talking. 2. It is possible for large numbers of droplet nuclei containing M tuberculosis bacteria to be generated during the surgical drainage, débridement, and syringe irrigation of abscesses caused by M tuberculosis. These procedures can produce such a high concentration of droplet nuclei that the ventilation system cannot remove them fast enough to protect the surgical staff from infection. 3. The unrecognized case of tuberculosis is much more likely to be the source of transmission of M tuberculosis than is the individual who has a diagnosis of TB or "rule-out TB." This is because once a diagnosis is known or suspected, interventions are initiated that make the patient less infectious.

Mycobacterium bovis in England and Wales: past, present and future

This report reviews the literature concerning tuberculosis resulting from infection with Mycobacterium bovis in man and cattle and summarises data derived from surveillance of M. bovis in England and Wales from 1986 to 1990. Of the 228 isolates of M. bovis examined in this period, 122 (53%) were from patients aged over 60 years and are largely the result of reactivation of infection acquired prior to the institution of control measures. However, eight isolates (3.5%) were from patients aged less than 30 years. The potential sources for these presumed primary infections include the few remaining cattle infected with M. bovis or infectious human cases in the United Kingdom. However, infections acquired abroad, especially in immigrants, may account for some of these cases. Outbreaks of tuberculosis due to M. bovis continue to occur in cattle. Wild animals, particularly badgers, have been implicated as reservoirs of the infection. However, man may also prove to be an important reservoir of M. bovis for cattle as well as humans.