Salmonellosis in elephants in managed care: report of 2 cases and literature review

In animals, salmonellosis is seen typically as enteritis and/or septicemia. Subclinical infection also occurs, and outwardly healthy animals can serve as reservoirs of infection. Reports of salmonellosis in elephants are rare, limited to a few serovars, and the gross and microscopic lesions of enteric salmonellosis in this species have not been described in detail. We present here, in 2 elephants in managed care settings, cases of salmonellosis that resulted from infection by Salmonella enterica serovar Muenchen and S. enterica serovar Montevideo, serovars that have not been described previously as the cause of salmonellosis in elephants, to our knowledge. We also review the literature on salmonellosis in elephants. Animal A, an adult Asian elephant that was euthanized because of gastrointestinal hemorrhage, had multifocal, necrotizing, suppurative enterocolitis, and necrotizing gastritis. Animal B, an adult African elephant with chronic, recurrent colic, followed by death, had necrotizing typhlocolitis. The origin of infection was not determined in either case. The animals came from different facilities and did not have a common feed source. Previously reported cases of salmonellosis in elephants were caused by Salmonella Dublin, Salmonella Typhimurium, or Salmonella Enteritidis. The definitive diagnosis of salmonellosis is made based on compatible gross and microscopic lesions, coupled with the detection of Salmonella spp. in the affected tissues. Effective biosecurity should be adopted to minimize the risk of salmonellosis in elephants in managed care.

Anthropogenic interferences lead to gut microbiome dysbiosis in Asian elephants and may alter adaptation processes to surrounding environments

Human activities interfere with wild animals and lead to the loss of many animal populations. Therefore, efforts have been made to understand how wildlife can rebound from anthropogenic disturbances. An essential mechanism to adapt to environmental and social changes is the fluctuations in the host gut microbiome. Here we give a comprehensive description of anthropogenically induced microbiome alterations in Asian elephants (n = 30). We detected gut microbial changes due to overseas translocation, captivity and deworming. We found that microbes belonging to Planococcaceae had the highest contribution in the microbiome alterations after translocation, while Clostridiaceae, Spirochaetaceae and Bacteroidia were the most affected after captivity. However, deworming significantly changed the abundance of Flavobacteriaceae, Sphingobacteriaceae, Xanthomonadaceae, Weeksellaceae and Burkholderiaceae. These findings may provide fundamental ideas to help guide the preservation tactics and probiotic replacement therapies of a dysbiosed gut microbiome in Asian elephants. More generally, these results show the severity of anthropogenic activities at the level of gut microbiome, altering the adaptation processes to new environments and the subsequent capability to maintain normal physiological processes in animals.

The VetMAX™ M. tuberculosis complex PCR kit detects MTBC DNA in antemortem and postmortem samples from white rhinoceros (Ceratotherium simum), African elephants (Loxodonta africana) and African buffaloes (Syncerus caffer)

BACKGROUND

Bovine tuberculosis and tuberculosis are chronic infectious diseases caused by the Mycobacterium tuberculosis complex members, Mycobacterium bovis and Mycobacterium tuberculosis, respectively. Infection with M. bovis and M. tuberculosis have significant implications for wildlife species management, public health, veterinary disease control, and conservation endeavours.

RESULTS

Here we describe the first use of the VetMAX™ Mycobacterium tuberculosis complex (MTBC) DNA quantitative real-time polymerase chain reaction (qPCR) detection kit for African wildlife samples. DNA was extracted from tissues harvested from 48 African buffaloes and MTBC DNA was detected (test-positive) in all 26 M. bovis culture-confirmed animals with an additional 12 PCR-positive results in culture-negative buffaloes (originating from an exposed population). Of six MTBC-infected African rhinoceros tested, MTBC DNA was detected in antemortem and postmortem samples from five animals. The PCR was also able to detect MTBC DNA in samples from two African elephants confirmed to have M. bovis and M. tuberculosis infections (one each). Culture-confirmed uninfected rhinoceros and elephants' samples tested negative in the PCR assay.

CONCLUSIONS

These results suggest this new detection kit is a sensitive screening test for the detection of MTBC-infected African buffaloes, African elephants and white rhinoceros.

Mycobacterium caprae Infection in Captive Borneo Elephant, Japan

In 2016, disseminated tuberculosis caused by Mycobacterium caprae was diagnosed in a captive Borneo elephant in Japan. The bacterium was initially identified from clinical isolates. An isolate collected during a relapse showed isoniazid monoresistance and a codon 315 katG mutation.

Presence of Helicobacter and Campylobacter species in faecal samples from zoo mammals

Helicobacter and Campylobacter species (spp.) colonize the gastrointestinal tract of various domesticated animals. Apart from their pathogenic significance in animals, several species are of zoonotic importance as well. For most non-domesticated animal spp., however, little is known on the presence and importance of these agents. Therefore, we investigated the presence of Helicobacter and Campylobacter spp. in marine and terrestrial zoo mammals. Faecal samples of various marine and terrestrial zoo mammals were collected from 6 different zoos in Belgium. These samples were tested for the presence of Helicobacter and Campylobacter spp. by isolation and direct demonstration of DNA using genus-specific PCRs, followed by sequencing of the obtained amplicons. Helicobacter spp. were detected in 12 and Campylobacter spp. in 5 of the 22 faecal samples from marine mammals. In 4 of 5 dolphins, H. cetorum was demonstrated, a well-known pathogen associated with gastritis and gastric ulceration in marine mammals. C. insulaenigrae was isolated from 4 of 6 sea lions and from 1 of 11 seals. To our knowledge, this is the first description of the presence of C. insulaenigrae on the European mainland. Helicobacter spp. were detected in 5 and Campylobacter spp. (mainly C. jejuni subsp. jejuni and C. coli) in 9 of the 26 faecal samples from terrestrial mammals. Potential novel enterohepatic Helicobacter spp. were detected in both marine and terrestrial zoo mammals. For the first time, the presence of several known and unknown Campylobacter and Helicobacter spp. was demonstrated in the gastrointestinal tract of various marine and terrestrial zoo mammals. Further investigation is needed on the pathogenic and zoonotic importance of these species.

Mycobacterium tuberculosis Infection in Free-Roaming Wild Asian Elephant

Postmortem examination of a wild Asian elephant at Rajiv Gandhi National Park, India, revealed nodular lesions, granulomas with central caseation, and acid-fast bacilli in the lungs. PCR and nucleotide sequencing confirmed the presence of Mycobacterium tuberculosis. This study indicates that wild elephants can harbor M. tuberculosis that can become fatal.

Streptococcus agalactiae in elephants - A comparative study with isolates from human and zoo animal and livestock origin

Streptococcus (S.) agalactiae represents a significant pathogen for humans and animals. However, there are only a few elderly reports on S. agalactiae infections in wild and zoo elephants even though this pathogen has been isolated comparatively frequently in these endangered animal species. Consequently, between 2004 and 2015, we collected S. agalactiae isolates from African and Asian elephants (n=23) living in four different zoos in Germany. These isolates were characterised and compared with isolates from other animal species (n=20 isolates) and humans (n=3). We found that the isolates from elephants can be readily identified by classical biochemistry and MALDI-TOF mass spectrometry. Further characterisations for epidemiological issues were achieved using Fourier transform-infrared spectroscopy, capsule typing and molecular fingerprinting (PFGE, RAPD PCR). We could demonstrate that our elephant isolate collection contained at least six different lineages that were representative for their source of origin. Despite generally broad antimicrobial susceptibility of S. agalactiae, many showed tetracycline resistance in vitro. S. agalactiae plays an important role in bacterial infections not only in cattle and humans, but also in elephants. Comparative studies were able to differentiate S. agalactiae isolates from elephants into different infectious clusters based on their epidemiological background.

The influence of social structure, habitat, and host traits on the transmission of Escherichia coli in wild elephants

Social structure is proposed to influence the transmission of both directly and environmentally transmitted infectious agents. However in natural populations, many other factors also influence transmission, including variation in individual susceptibility and aspects of the environment that promote or inhibit exposure to infection. We used a population genetic approach to investigate the effects of social structure, environment, and host traits on the transmission of Escherichia coli infecting two populations of wild elephants: one in Amboseli National Park and another in Samburu National Reserve, Kenya. If E. coli transmission is strongly influenced by elephant social structure, E. coli infecting elephants from the same social group should be genetically more similar than E. coli sampled from members of different social groups. However, we found no support for this prediction. Instead, E. coli was panmictic across social groups, and transmission patterns were largely dominated by habitat and host traits. For instance, habitat overlap between elephant social groups predicted E. coli genetic similarity, but only in the relatively drier habitat of Samburu, and not in Amboseli, where the habitat contains large, permanent swamps. In terms of host traits, adult males were infected with more diverse haplotypes, and males were slightly more likely to harbor strains with higher pathogenic potential, as compared to adult females. In addition, elephants from similar birth cohorts were infected with genetically more similar E. coli than elephants more disparate in age. This age-structured transmission may be driven by temporal shifts in genetic structure of E. coli in the environment and the effects of age on bacterial colonization. Together, our results support the idea that, in elephants, social structure often will not exhibit strong effects on the transmission of generalist, fecal-oral transmitted bacteria. We discuss our results in the context of social, environmental, and host-related factors that influence transmission patterns.

Serodiagnosis of tuberculosis in Asian elephants (Elephas maximus) in Southern India: a latent class analysis

BACKGROUND

Mycobacterium tuberculosis, a causative agent of chronic tuberculosis disease, is widespread among some animal species too. There is paucity of information on the distribution, prevalence and true disease status of tuberculosis in Asian elephants (Elephas maximus). The aim of this study was to estimate the sensitivity and specificity of serological tests to diagnose M. tuberculosis infection in captive elephants in southern India while simultaneously estimating sero-prevalence.

METHODOLOGY/PRINCIPAL FINDINGS

Health assessment of 600 elephants was carried out and their sera screened with a commercially available rapid serum test. Trunk wash culture of select rapid serum test positive animals yielded no animal positive for M. tuberculosis isolation. Under Indian field conditions where the true disease status is unknown, we used a latent class model to estimate the diagnostic characteristics of an existing (rapid serum test) and new (four in-house ELISA) tests. One hundred and seventy nine sera were randomly selected for screening in the five tests. Diagnostic sensitivities of the four ELISAs were 91.3-97.6% (95% Credible Interval (CI): 74.8-99.9) and diagnostic specificity were 89.6-98.5% (95% CI: 79.4-99.9) based on the model we assumed. We estimate that 53.6% (95% CI: 44.6-62.8) of the samples tested were free from infection with M. tuberculosis and 15.9% (97.5% CI: 9.8 - to 24.0) tested positive on all five tests.

CONCLUSIONS/SIGNIFICANCE

Our results provide evidence for high prevalence of asymptomatic M. tuberculosis infection in Asian elephants in a captive Indian setting. Further validation of these tests would be important in formulating area-specific effective surveillance and control measures.

Pulmonary aspergillosis in an African elephant (Loxodonta africana)

A 26-year-old female African elephant (Loxodonta africana) with a history of purulent pododermatitis, recurrent abdominal pain, and severe weight loss died spontaneously after a period of deteriorating disease. The main pathological finding was a severe bilateral pyogranulomatous, partially necrotizing pneumonia with numerous intralesional fungal hyphae. At microbiological examination Aspergillus spp. were isolated. The present case indicates that mycotic pneumonia should to be considered as a differential diagnosis of pulmonary disorders in elephants.

Methicillin-resistant Staphylococcus aureus skin infections from an elephant calf--San Diego, California, 2008

Methicillin-resistant Staphylococcus aureus (MRSA) infections are a major cause of human skin and soft tissue infections in the United States. MRSA colonization and infection also have been observed in turtles, bats, seals, sheep, rabbits, rodents, cats, dogs, pigs, birds, horses, and cattle, and MRSA infections with an epidemiologic link to animal contact have been reported in veterinary personnel, pet owners, and farm animal workers. On January 29, 2008, the County of San Diego Health and Human Services Agency was notified of skin pustules on an African elephant (Loxodonta africana) calf and three of its caretakers at a zoo in San Diego County. After each of these infections (including the calf's infection) was laboratory confirmed as MRSA, an outbreak investigation and response was initiated by the zoo and the agency. This report summarizes the results of that investigation, which identified two additional confirmed MRSA infections, 15 suspected MRSA infections, and three MRSA-colonized persons (all among calf caretakers), and concluded that infection of the elephant calf likely came from a colonized caretaker. This is the first reported case of MRSA in an elephant and of suspected MRSA transmission from an animal to human caretakers at a zoo. Recommendations for preventing MRSA transmission in zoo settings include 1) training employees about their risks for infection and the recommended work practices to reduce them; 2) performing proper hand hygiene before and after animal contact; 3) using personal protective equipment (PPE) when working with ill or infected animals, especially during wound treatment; and 4) cleaning and disinfecting contaminated equipment and surfaces.

Tuberculosis as a zoonosis from a veterinary perspective

Tuberculosis is an important disease among many zoonoses, because both Mycobacterium tuberculosis and Mycobacterium bovis, which are the major causes of tuberculosis, are highly pathogenic, infect many animal species and thus are likely to be the source of infection in humans. In particular, monkeys are highly susceptible to these bacteria and are important spreaders. Recently, two outbreaks of M. tuberculosis occurred in four different kinds of monkeys and humans were also infected with the disease in Japan. In zoos, tuberculosis was reported not only in monkeys, but also in several different kinds of animals, including elephants. Pets such as dogs and cats are believed to be generally less susceptible to M. tuberculosis, but in this article we introduce a case of infection from man to dog by close contact. Japan is one of the few countries that have been able to control M. bovis infection. In other countries, however, cases of bovine tuberculosis and human M. bovis infection have been reported, and thus further attention is still required in the future.

Two cases of atypical mycobacteriosis caused by Mycobacterium szulgai associated with mortality in captive African elephants (Loxodonta africana)

Mycobacterium szulgai was associated with mortality in two captive African elephants (Loxodonta africana) housed at Lincoln Park Zoo. The first elephant presented with severe, acute lameness of the left rear limb. Despite extensive treatments, the animal collapsed and died 13 mo after initial presentation. Necropsy revealed osteomyelitis with loss of the femoral head and acetabulum and pulmonary granulomas with intralesional M. szulgai. The second elephant collapsed during transport to another institution with no premonitory clinical signs. This animal was euthanized because of prolonged recumbency. Granulomatous pneumonia with intralesional M. szulgai was found at necropsy. Two novel immunoassays performed on banked serum samples detected antibody responses to mycobacterial antigens in both infected elephants. It was not possible to determine when the infection was established or how the elephants were infected. When reviewing the epidemiology of this organism in humans, however, transmission between elephants seemed unlikely because human-to-human transmission of this organism has never been reported and a third elephant in the herd was not affected. In addition to Mycobacterium bovis and Mycobacterium tuberculosis, atypical mycobacterial organisms need to be considered potentially pathogenic in elephants.

Fatal enterocolitis in Asian elephants (Elephas maximus) caused by Clostridium difficile

Two cases of fatal enteritis caused by Clostridium difficile in captive Asian elephants are reported from an outbreak affecting five females in the same zoo. Post mortem examination including histopathology demonstrated fibrinonecrotic enterocolitis. C. difficile was isolated by selective cultivation from two dead and a third severely affected elephant. Four isolates were obtained and found positive for toxin A and B by PCR. All isolates were positive in a toxigenic culture assay and toxin was demonstrated in the intestinal content from one of the fatal cases and in a surviving but severely affected elephant. PCR ribotyping demonstrated that the C. difficile isolates shared an identical profile, which was different from an epidemiologically unrelated strain, indicating that the outbreak was caused by the same C. difficile clone. It is speculated that the feeding of large quantities of broccoli, a rich source of sulforaphane, which has been shown to inhibit the growth of many intestinal microorganisms may have triggered a subsequent overgrowth by C. difficile. This is the first report of C. difficile as the main cause of fatal enterocolitis in elephants. The findings emphasize the need to regard this organism as potentially dangerous for elephants and caution is recommended concerning antibiotic treatment and feeding with diets containing antimicrobials, which may trigger an expansion of a C. difficile population in the gut.

Mycobacterium elephantis sp. nov., a rapidly growing non-chromogenic Mycobacterium isolated from an elephant

A strain isolated from a lung abscess in an elephant that died from chronic respiratory disease was found to have properties consistent with its classification in the genus Mycobacterium. An almost complete sequence of the 165 rDNA of the strain was determined following the cloning and sequencing of the amplified gene. The sequence was aligned with those available on mycobacteria and phylogenetic trees inferred by using three tree-making algorithms. The organism, which formed a distinct phyletic line within the evolutionary radiation occupied by rapidly growing mycobacteria, was readily distinguished from members of validly described species of rapidly growing mycobacteria on the basis of its mycolic acid pattern and by a number of other phenotypic features, notably its ability to grow at higher temperatures. The type strain is Mycobacterium elephantis DSM 44368T.

Ulcerative pododermatitis in free-ranging African elephant (Loxodonta africana) in the Kruger National Park

The occurrence of severe lameness in adult African elephant bulls in a shrub Mopane (Colophospermum mopane) ecosystem was investigated. Large ulcers in the soles of at least one front foot were seen in each of the recorded cases. Microscopically, the lesion can be described as a severe, chronic-active, ulcerative, bacterial pododermatitis (complicated by hypersensitivity/septic vasculitis). A variety of bacteria were isolated from these lesions as well as from regional lymph nodes. Streptococcus agalactiae was the most consistent isolate, while Dichelobacter nodosus, the only organism known to be involved with foot disease in domestic ruminants, was isolated from two cases. Contributory factors such as body mass, portal of entry and origin of potential pathogens may have predisposed to the development of the lesions.

Fermentation of cellulose and production of cellulolytic and xylanolytic enzymes by anaerobic fungi from ruminant and non-ruminant herbivores

Four anaerobic fungi were grown on filter paper cellulose and monitored over a 7-8 days period for substrate utilisation, fermentation products, and secretion of cellulolytic and xylanolytic enzymes. Two of the fungi (N1 and N2) were Neocallimastix species isolated from a ruminant (sheep) and the other two fungi were Piromyces species (E2 and R1) isolated from an Indian Elephant and an Indian Rhinoceros, respectively. The tested anaerobic fungi degraded the filter paper cellulose almost completely and estimated cellulose digestion rates were 0.25, 0.13, 0.21 and 0.18 g.l-1.h-1 for strains E2, N1, N2, R1, respectively. All strains secreted cellulolytic and xylanolytic enzymes, including endoglucanase, exoglucanase, beta-glucosidase and xylanase. Strain E2 secreted the highest levels of enzymes in a relatively short time. The product formation on avicel by enzymes secreted by the four fungi was studied. Both in the presence and absence of glucurono-1,5-delta-lactone, a specific inhibitor of beta-glucosidase, mainly glucose was formed but no cellobiose. Therefore the exoglucanase secreted by the four fungi is probably a glucohydrolase.

Comparison of growth characteristics of anaerobic fungi isolated from ruminant and non-ruminant herbivores during cultivation in a defined medium

Anaerobic fungi were isolated from rumen fluid of a domestic sheep (Ovis aries; a ruminant) and from faeces of five non-ruminants: African elephant (Loxodonta africana), black rhinoceros (Diceros bicornis), Indian rhinoceros (Rhinoceros unicornis), Indian elephant (Elephas maximus) and mara (Dolichotis patagonum). The anaerobic fungus isolated from the sheep was a Neocallimastix species and the isolates from non-ruminants were all species similar to Piromyces spp. A defined medium is described which supported growth of all the isolates, and was used to examine growth characteristics of the different strains. For each fungus the lipid phosphate content was determined after growth on cellobiose and the resulting values were used to estimate fungal biomass after growth on solid substrates. The ability of isolates from ruminants and non-ruminants to digest both wheat straw and cellulose was comparable. More than 90% and 60%, respectively, of filter paper cellulose and wheat straw were digested by most strains within 60-78 h. Growth of two fungi, isolated from rumen fluid of a sheep (Neocallimastix strain N1) and from faeces of an Indian rhinoceros (Piromyces strain R1), on cellobiose was studied in detail. Fungal growth yields on cellobiose were 64.1 g (mol substrate)-1 for N1 and 34.2 g mol-1 for R1. The major fermentation products of both strains were formate, lactate, acetate, ethanol and hydrogen.

Comparative analysis of the genomes of orthopoxviruses isolated from elephant, rhinoceros, and okapi by restriction enzymes. Brief report

Orthopoxviruses from different zoo-kept mammalian species including Elephas maximus (8 isolates), Ceratotherium simum (1 isolate), and Okapia johnstoni (2 isolates) were characterized by restriction enzyme analysis of the viral genome. The four enzymes BamHI, MluI, NcoI, and SalI were found to be optimal for strain differentiation.

Death of an African elephant from probable toxemia attributed to chronic pulpitis

A 31-year-old captive male African elephant (Loxodonta africana) of 5,000-kg body weight died suddenly in ventral recumbency. Lesions seen at necropsy were bilateral purulent pulpitis and periodontitis of both tusks, serous atrophy of coronary groove fat, Grammocephalus cholangitis, myocardial and skeletal lipofuscinosis, and scattered segmental necrosis in the pectoral muscles. Nonhemolytic streptococci, Corynebacterium sp, Peptostreptococcus anaerobius, Fusobacterium nucleatum, and Bacteroides sp, were recovered from the exudate around one or both tusks. We postulated that the elephant died of hypoxia from prolonged ventral recumbency because of weakness and inability to rise secondary to toxemia from bilateral pulpitis and periodontitis.

Comparison of cowpox-like viruses isolated from European zoos. Brief report

Poxviruses isolated from captive carnivores in Russia (Moscow virus) and elephants in Germany (elephant virus) were very closely-related to cowpox virus. Immunological analysis with absorbed sera separated elephant virus but not cowpox and Moscow virus, whereas polypeptide analysis separated cowpox but not elephant and Moscow virus. A combination of biological tests separated all three. The epidemiological implications are briefly reviewed.

Laboratory characteristics of poxviruses isolated from captive elephants in Germany

Proxviruses isolated from captive elephants in Germany have been characterized. Although related to vaccinia and even more closely to cowpox virus, the separate identity of elephantpox virus was established by both biological and serological methods. Elephantpox virus produces A-type inclusions in infected cells, as did cowpox, but had a lower ceiling temperature, was more heat resistant and affected rabbits differently. Cross neutralization tests on absorbed sera indicated that elephantpox, cowpox and vaccinia viruses shared one surface antigen, that elephantopox and vaccinia shared an antigen absent from cowpox, and that vaccinia virus had a surface antigen absent from elephantopox and cowpox viruses.

Mycobacteria isolated from exotic animals

Mycobacteria were isolated from 263 of 474 specimens submitted from captive exotic (nondomesticated) animals over a 5-year period. Mycobacterium avium was isolated from 128 animals originating in 13 states and the District of Columbia; serotype 1 accounted for 65 of the isolations. Mycobacterium bovi was isolated from 74 animals in 7 zoos, 7 game parks, and 4 primate colonies in 1, states: Mycobacterium tuberculosis was isolated from 29 animals originating 9 stats; and Mycobacterium fortuitum, Mycobacterium chelonei, Mycobacterium scrofulaceum, and Mycobacterium spp. The widespread occurrence of tuberculosis in exotic animals maintained in captivity emphasizes the public health importance of these infections.