Strongyloides in non-human primates: significance for public health control

Primates are an important source of infectious disease in humans. Strongyloidiasis affects an estimated 600 million people worldwide, with a global distribution and hotspots of infection in tropical and subtropical regions. Recently added to the list of neglected tropical diseases, global attention has been demanded in the drive for its control. Through a literature review of Strongyloides in humans and non-human primates (NHP), we analysed the most common identification methods and gaps in knowledge about this nematode genus. The rise of molecular-based methods for Strongyloides detection is evident in both humans and NHP and provides an opportunity to analyse all data available from primates. Dogs were also included as an important host species of Strongyloides and a potential bridge host between humans and NHP. This review highlights the lack of molecular data across all hosts-humans, NHP and dogs-with the latter highly underrepresented in the database. Despite the cosmopolitan nature of Strongyloides, there are still large gaps in our knowledge for certain species when considering transmission and pathogenicity. We suggest that a unified approach to Strongyloides detection be taken, with an optimized, repeatable molecular-based method to improve our understanding of this parasitic infection. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.

Gastrointestinal Parasites Affecting Non-Human Primates That Are Kept Ex Situ and Their Handlers in Different Brazilian Institutions: Diagnosis and Analysis of Risk Factors

AIM

Determining gastrointestinal parasites' frequency in non-human primates (NHPs) and handlers in different Brazilian institutions, and associate it with management information.

METHODS

Different institutions in São Paulo (A), Brasília (B), Rio de Janeiro (C), Pará (D) and Santa Catarina (E) were included in the study. Fecal samples were processed by using coproparasitological techniques; information about NHP handling and professionals' routine were collected through the use of questionnaires.

RESULTS

In total, 33.1% of 511 NHP samples were positive for parasites; the Entamoebidae Group and Strongyloides sp.-compatible eggs were the most detected protozoa and helminths, respectively. The Entamoebidae Group was mainly diagnosed in Alouatta from Institutions E and D, and was also the only parasite detected in handlers. Strongyloides-compatible eggs were mostly evident in fecal samples collected from Cebidae from Institutions B and D. Some risk factors associated with parasite infection were a high number of animals in the same enclosure and their use for research protocol purposes, whereas quarantine, a post-infection vacant period in enclosures and antiparasitic supply were categorized as protective factors against these agents' infection.

CONCLUSIONS

Parasites showing different transmission routes but concomitantly circulating in NHP institutions located in different Brazilian regions were identified in the current study, with an emphasis on those presenting zoonotic potential.

Cancerogenic parasites in veterinary medicine: a narrative literature review

Parasite infection is one of the many environmental factors that can significantly contribute to carcinogenesis and is already known to be associated with a variety of malignancies in both human and veterinary medicine. However, the actual number of cancerogenic parasites and their relationship to tumor development is far from being fully understood, especially in veterinary medicine. Thus, the aim of this review is to investigate parasite-related cancers in domestic and wild animals and their burden in veterinary oncology. Spontaneous neoplasia with ascertained or putative parasite etiology in domestic and wild animals will be reviewed, and the multifarious mechanisms of protozoan and metazoan cancer induction will be discussed.

Pathologic characteristics of infectious diseases in macaque monkeys used in biomedical and toxicologic studies

Nonhuman primates (NHPs), which have many advantages in scientific research and are often the only relevant animals to use in assessing the safety profiles and biological or pharmacological effects of drug candidates, including biologics. In scientific or developmental experiments, the immune systems of animals can be spontaneously compromised possibly due to background infection, experimental procedure-associated stress, poor physical condition, or intended or unintended mechanisms of action of test articles. Under these circumstances, background, incidental, or opportunistic infections can seriously can significantly complicate the interpretation of research results and findings and consequently affect experimental conclusions. Pathologists and toxicologists must understand the clinical manifestations and pathologic features of infectious diseases and the effects of these diseases on animal physiology and experimental results in addition to the spectrum of infectious diseases in healthy NHP colonies. This review provides an overview of the clinical and pathologic characteristics of common viral, bacterial, fungal, and parasitic infectious diseases in NHPs, especially macaque monkeys, as well as methods for definitive diagnosis of these diseases. Opportunistic infections that can occur in the laboratory setting have also been addressed in this review with examples of cases of infection disease manifestation that was observed or influenced during safety assessment studies or under experimental conditions.

Gastrointestinal helminth parasites of wild ungulates in Hirpora Wildlife Sanctuary, Kashmir, India

Parasitic infection represents an emerging threat to wild ungulates and a challenge to their management. Although a lot of work has been carried out on helminth parasitic infestation of domestic ungulates of Kashmir but the data pertaining to this aspect of wild ungulates has been ignored. The study on gastrointestinal helminth parasitic infestation of wild ungulates was carried out during post livestock grazing period (November to May) of 2018/2019 in Hirpora Wildlife sanctuary (HWLS) to fill the gap in the existing literature. During the study fresh faecal samples of musk deer Moschus spp. (n = 44) and markhor Capra falconeri (n = 41) were collected and examined qualitatively and quantitatively for gastrointestinal helminth parasites. A total of seven helminth parasites were recorded which are arranged in the descending order of their overall prevalence as Haemonchus spp. (44.70%), Nematodirus spp. (40%), Trichuris spp. (37.64%), Strongyloides spp. (34.11%) Trichostrongylus spp. (28.23%) Moniezia spp. (23.52%) and Fasciola spp. (20%). The mean EPG (eggs per gram) of different parasites showed a considerable variation in both the wild ungulates. The highest mean EPG was that of Haemonchus spp. and the lowest mean EPG was that of Fasciola spp. in both hosts. A statistically significant difference was observed in the mean EPG of different parasites between two wild hosts (t = 3.606, p = 0.01) .

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND): Non-proliferative and Proliferative Lesions of the Non-human Primate (M. fascicularis)

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions Project (www.toxpath.org/inhand.asp) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in most tissues and organs from the nonhuman primate used in nonclinical safety studies. Some of the lesions are illustrated by color photomicrographs. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. Relevant infectious and parasitic lesions are included as well. A widely accepted and utilized international harmonization of nomenclature for lesions in laboratory animals will provide a common language among regulatory and scientific research organizations in different countries and increase and enrich international exchanges of information among toxicologists and pathologists.

Diversity of parasites in two captive chimpanzee populations in southern Gabon

Captive chimpanzees living in confined environments like sanctuaries or primatology centers are frequently affected by gastrointestinal parasites. Some of these are likely to be transmitted to humans and may seriously affect public health. However little information is currently available on the gastrointestinal parasites of primates living in such environments. Here, we characterize the diversity and prevalence of gastrointestinal parasites in two populations of captive chimpanzees living in south-eastern Gabon. Our study reveals that at least nine parasite species infect the chimpanzees with high prevalence, including several helminths (Ascaris spp., Enterobius spp., Strongyloides spp., Trichuris spp., Hymenolepis spp., Mammomonogamus spp), three protozoa (Balantioides spp., Entamoeba spp. and Troglodytella spp) and several unidentified parasites. All the parasite taxa we identified had previously been identified in other primates, including humans. Age, sex and site type may influence infection rates and/or parasite diversity found in a particular host.

Idiopathic Colitis in Rhesus Macaques Is Associated With Dysbiosis, Abundant Enterochromaffin Cells and Altered T-Cell Cytokine Expression

Idiopathic chronic diarrhea (ICD) is a common ailment affecting captive rhesus macaques ( Macaca mulatta). ICD cases are characterized by diarrhea in the absence of commonly identified diarrheal pathogens and multiple recurrences even after supportive therapy. Histologically, the disease is characterized by lymphoplasmacytic colitis. We identified 35 rhesus macaques euthanized for ICD during a 7-month period and described demographic, clinical, histologic, and immunologic commonalities. We found a trend of historic Campylobacter spp. and trichomonad infections. Furthermore, rhesus macaques with ICD demonstrated loss of normal colonic adherent bacterium, identified in this study as Helicobacter macacae; increased abundance of Pentatrichomonas hominis; and increased frequency of colonic serotonin-positive enterochromaffin cells. Interestingly, colonic and ileal T-helper cells of animals with ICD manifested decreased capacity for expression of certain cytokines, in particular interleukin (IL)-4 and IL-13. These data further describe a common ailment and suggest new avenues to identify complex interactions involved in the etiology of recurring diarrhea in young rhesus macaques.

Seasonality, richness and prevalence of intestinal parasites of three neotropical primates (Alouatta seniculus, Ateles hybridus and Cebus versicolor) in a fragmented forest in Colombia

Studies on parasites infecting non-human primates are essential to better understand the potential threat to humans of zoonoses transmission, particularly under the current processes of pervasive land use change and biodiversity loss. The natural ecosystems in the Middle Magdalena river basin in Colombia have suffered a dramatic reduction and transformation into pastures and agroindustrial monocultures, threatening their biodiversity, and probably affecting the dynamics between parasites and their hosts, as well as altering the disease transmission cycles between wild populations and humans. This study evaluated seasonality, prevalence and richness of intestinal parasites in three species of neotropical primates: Cebus versicolor, Ateles hybridus and Alouatta seniculus, in a fragmented forest in the Middle Magdalena river valley, Colombia. One hundred and eighty five faecal samples were collected between 2010 and 2015. Direct faecal smears were performed with saline solution (0.85%) and iodine solution (1%), in order to identify larvae and eggs based on their morphology. A large proportion of the samples examined (72.9%) was positive for intestinal parasites; seven families of nematodes were identified: Trichuridae, Trichostrongylidae, Oxyuridae, Strongyloididae, Ancylostomatidae, Ascarididae and Gnathostomatidae, two of protozoans: Entamoebidae and Balantiididae, as well as some eggs of trematodes, cestodes and acanthocephalans. Additionally, DNA extraction and sequencing were conducted on 30 faecal samples in order to identify Giardia sp. and Blastocystis hominis, two parasite species also present in humans. Molecular testing for Giardia sp. was negative and Blastocystis hominis was identified in a single sample of Alouatta seniculus. No clear patterns were observed for prevalence of intestinal parasites according to the season; nonetheless, parasite species richness was higher during the dry season. This study builds on our current understanding of intestinal parasites infecting wild neotropical primates and provides novel information on the patterns of intestinal parasites in primate communities exposed to anthropogenic disturbance.

Mitochondrial DNA diversity in the acanthocephalan Prosthenorchis elegans in Colombia based on cytochrome c oxidase I (COI) gene sequence

Prosthenorchis elegans is a member of the Phylum Acanthocephala and is an important parasite affecting New World Primates in the wild in South America and in captivity around the world. It is of significant management concern due to its pathogenicity and mode of transmission through intermediate hosts. Current diagnosis of P. elegans is based on the detection of eggs by coprological examination. However, this technique lacks both specificity and sensitivity, since eggs of most members of the genus are morphologically indistinguishable and shed intermittently, making differential diagnosis difficult, and coprological examinations are often negative in animals severely infected at death. We examined sequence variation in 633 bp of mitochondrial DNA (mtDNA) cytochrome c oxidase I (COI) sequence in 37 isolates of P. elegans from New World monkeys (Saguinus leucopus and Cebus albifrons) in Colombia held in rescue centers and from the wild. Intraspecific divergence ranged from 0.0 to 1.6% and was comparable with corresponding values within other species of acanthocephalans. Furthermore, comparisons of patterns of sequence divergence within the Acanthocephala suggest that Prosthenorchis represents a separate genus within the Oligacanthorhynchida. Six distinct haplotypes were identified within P. elegans which grouped into one of two well-supported mtDNA haplogroups. No association between haplogroup/haplotype, holding facility and species was found. This information will help pave the way to the development of molecular-based diagnostic tools for the detection of P. elegans as well as furthering research into the life cycle, intermediate hosts and epidemiological aspects of the species.

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First report of mitochondrial DNA sequence in Prosthenorchis sp.

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Surprising genetic diversity in Prosthenorchis elegans.

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Six different haplotypes detected within Prosthenorchis elegans which grouped into one of two well-supported mtDNA lineages.

Pentatrichomonas hominis in laboratory-bred common marmosets

Trichomonadid protozoa have been found in the intestinal tracts of common marmosets (Callithrix jacchus). However, there is little information available on species identification and the pathogenicity of these trichomonads. In this study, we conducted a fecal survey of a common marmoset colony maintained as laboratory animals in Japan and identified the trichomonad species. Screening using a fecal smear examination revealed that 66% (58/88) of the marmosets had trichomonadid trophozoites in their feces. The trichomonads were found in both normal feces (31/49, 63%) and diarrhea (27/39, 69%), with no significant difference in frequency. The protozoa were identified as Pentatrichomonas hominis using morphological characters and the 100% identity of the nucleotide sequence of the partial 18S rRNA gene (297 bp). The intraspecific genetic variability between P. hominis from the marmosets in this study and P. hominis from other reported mammal hosts was ≤1% in the nucleotide sequence, including the internal transcribed spacer (ITS)-1, 5.8S rRNA gene, and ITS-2 (293 bp). P. hominis inhabits the large intestine of various mammalian hosts, including primates, and is considered nonpathogenic. These results suggest that P. hominis is transmitted among marmosets and other mammals but is not a primary cause of bowel disease in marmosets.

Gastrointestinal Parasites of Ecuadorian Mantled Howler Monkeys (Alouatta palliata aequatorialis) Based on Fecal Analysis

An analysis of gastrointestinal parasites of Ecuadorian mantled howler monkeys, Alouatta palliata aequatorialis, was conducted based on examination of fecal smears, flotations, and sedimentations. At least 1 type of parasite was detected in 97% of the 96 fecal samples screened across 19 howler monkey groups using these techniques. Samples averaged 3.6 parasite species per individual (±1.4 SD). Parasites included species representing genera of 2 apicomplexans: Cyclospora sp. (18% of individual samples) and Isospora sp. (3%); 6 other protozoa: Balantidium sp. (9%), Blastocystis sp. (60%), Chilomastix sp. (4%), Dientamoeba sp. (3%), Entamoeba species (56%), Iodamoeba sp. (5%); 4 nematodes: Enterobius sp. (3%), Capillaria sp. (78%), Strongyloides spp. (88%) which included 2 morphotypes, Trypanoxyuris sp. (12%); and the platyhelminth Controrchis sp. (15%). A statistically significant positive correlation was found between group size and each of 3 different estimators of parasite species richness adjusted for sampling effort (ICE: r(2) = 0.24, P = 0.05; Chao2: r(2) = 0.25, P = 0.05, and Jackknife: r(2) = 0.31, P = 0.03). Two significant associations between co-infecting parasites were identified. Based on the prevalence data, individuals infected with Balantidium sp. were more likely to also be infected with Isospora sp. (χ(2) = 6.02, P = 0.01), while individuals harboring Chilomastix sp. were less likely to have Capillaria sp. present (χ(2) = 4.03, P = 0.04).

Looking in apes as a source of human pathogens

Because of the close genetic relatedness between apes and humans, apes are susceptible to many human infectious agents and can serve as carriers of these pathogens. Consequently, they present a serious health hazard to humans. Moreover, many emerging infectious diseases originate in wildlife and continue to threaten human populations, especially vector-borne diseases described in great apes, such as malaria and rickettsiosis. These wild primates may be permanent reservoirs and important sources of human pathogens. In this special issue, we report that apes, including chimpanzees (Pan troglodytes), bonobos (Pan paniscus), gorillas (Gorilla gorilla and Gorilla beringei), orangutans (Pongo pygmaeus and Pongo abelii), gibbons (Hylobates spp., Hoolock spp. and Nomascus spp) and siamangs (Symphalangus syndactylus syndactylus and Symphalangus continentis), have many bacterial, viral, fungal and parasitic species that are capable of infecting humans. Serious measures should be adopted in tropical forests and sub-tropical areas where habitat overlaps are frequent to survey and prevent infectious diseases from spreading from apes to people.

Balantidium coli and other gastrointestinal parasites in captives non-human primates of the Rio de Janeiro, Brazil

BACKGROUND

Parasites are agents of diarrhea in captive non-human primates (NHP). To broaden information about those etiological agents in captive animals in Brazil, gastrointestinal parasites in captive NHP were researched in nurturing Centers of Rio de Janeiro State.

METHODS

Fecal samples were collected from primates, of which 960 came from the Research Center (Cecal/Fiocruz) and 115 from the Primate Center (CPRJ/Inea). The study involved species of the New World (NW) primates and of the Old World (OW).

RESULTS

The estimated prevalence was 56.7%, of which 91.3% presented protozoans and 7.4% presented helminths. Statistical difference between the nurturing centers occurred in the overall value of parasitosis and in the isolated frequency of Balantidium coli and Entamoeba sp., especially in the samples of OW primates living in Cecal.

CONCLUSIONS

These results demonstrated the need for implements of sanitation programs in the sites for captive primates nurturing.

Strongyloides cebus (Nematoda: Strongyloididae) in Lagothrix cana (Primates: Atelidae) from the Brazilian Amazon: aspects of clinical presentation, anatomopathology, treatment, and parasitic biology

Abstract :  Seven cases of parasitism by Strongyloides cebus were identified in Lagothrix cana from Brazil. Aspects of the clinical presentation, treatment, pathology, and parasitic biology of these infections are described. Moderate to severe disease was observed, requiring hospitalization of 3 primates, and diarrhea was the most common clinical sign described. One L. cana individual died, for which ulcerative enteritis was the major finding upon histopathological analysis. The use of ivermectin in these atelids was safe and effective against the parasite. Parallel attempts to experimentally infect gerbils with the parasite failed. Lagothrix cana is presented as a new host for S. cebus. The evidence that Strongyloides infections are common in nonhuman primates under free-living conditions, and even more prevalent in captive animals, likely represents a neglected problem.

Trypanoxyuris (Paraoxyuronema)lagothricis (Nematoda: Oxyuridae) in Lagothrix cana (Primates: Atelidae) from Brazil

During necropsy of a specimen of Lagothrix cana (É. Geoffroy, 1812) (Primates: Atelidae) from the Brazilian Amazon, pinworms were found in the large intestine. The intensity of infection was 64 parasites (17 males and 47 females) and there were no gross pathological changes related to parasitism. After morphological analysis the parasites were identified asTrypanoxyuris (Paraoxyuronema)lagothricis (Buckley, 1931) (Nematoda: Oxyuridae). This is the first record of this oxyurid species in primates in Brazil.

Massive visceral pentastomiasis in a long-tailed macaque - an incidental finding

BACKGROUND

An unusual case of visceral pentastomiasis in a male adult long-tailed macaque imported from China is reported.

METHODS

The monkey was part of a toxicologic study. A massive accumulation of C-shaped parasites in various visceral organs was found post-mortem.

RESULTS

Based on the morphology of the nymphs, pentastomiasis was diagnosed etiopathologically. The pentastome genus and species was identified as Armillifer agkistrodontis by PCR and respective sequencing.

CONCLUSION

Molecular diagnostic methods are necessary tools to determine the exact species involved.

Systemic spironucleosis in 2 immunodeficient rhesus macaques (Macaca mulatta)

Spironucleus spp are parasites of fish and terrestrial vertebrates, including mice and turkeys, that rarely cause extraintestinal disease. Two rhesus macaques (Macaca mulatta) were experimentally inoculated with simian immunodeficiency virus mac251. Both progressed to simian acquired immune deficiency syndrome within 1 year of inoculation and developed systemic protozoal infections in addition to common opportunistic infections, including rhesus cytomegalovirus, rhesus lymphocryptovirus, and rhesus adenovirus. In the first case, the protozoa were associated with colitis, multifocal abdominal abscessation, and lymphadenitis. In the second case, they were one of a number of organisms associated with extensive pyogranulomatous pneumonia and colitis. Ultrastructural, molecular, and phylogenetic analysis revealed the causative organism to be a species of Spironucleus closely related to Spironucleus meleagridis of turkeys. This report is the first of extraintestinal infection with Spironucleus sp in higher mammals and expands the list of opportunistic infections found in immunocompromised rhesus macaques.

The impact of concomitant infections by Trypanosoma cruzi and intestinal helminths on the health of wild golden and golden-headed lion tamarins

A 4-year longitudinal epidemiological study was carried out to evaluate the effect of infection by Trypanosoma cruzi and three intestinal helminth species on the health of golden and golden-headed lion tamarins. We evaluated health using analysis of blood counts, serum proteins, electrophoretograms, electrocardiograms and a health ranking based on physiological parameters. Among the helminths, Trichostrongylidae was demonstrated as the most pathogenic, followed by Prosthenorchis sp.; concomitant infection by Spiruridae may exacerbate the negative effects of the other two helminths. T. cruzi infection was not highly detrimental to the health of the study animals and was correlated with increased resilience to helminths. Tamarins younger than 1-year of age or older than 4-years had lower health condition. Golden-headed lion tamarins were in lower health condition because of higher parasitic prevalence. Our data suggest that when parasite community pathogenicity and prevalence are high, natural selection will allow survival only of lion tamarins in the best health condition.

Prevalence and intensity of intestinal helminths found in free-ranging golden lion tamarins (Leontopithecus rosalia, Primates, Callitrichidae) from Brazilian Atlantic forest

Helminth identification and egg counts were performed in 316 fecal samples during 4 years in 199 golden lion tamarins (GLTs), Leontopithecus rosalia, from two Brazilian conservation units. Tamarin sex and age, area of occurrence and helminth co-infection were tested as potential factors that could affect helminth prevalence and egg shedding in host individuals. Three nematodes species were found at low prevalences but not in both conservation units: Ancylostomatidae (12%), Ascarididae (1%) and Tripanoxyuris minutus, an Oxyuridae (4%). Three other species had high prevalences and were found in both conservation units: one acanthocephalan, Oncicola sp. (30%), and two nematodes, Spiruridae (24%), and Trichostrongylidae (31%). These three latter helminths had distinct prevalences between the conservation units, probably due to differences in availability of helminth infective stages in each area. Prevalences were greater in females for all helminth species; this was especially the case for Oncicola sp. Sex and age differences in helminth prevalence may be associated with changes in sexual steroid levels that accompany age and reproductive status. Frequency of simultaneous infections by the two helminths considered most pathogenic (Oncicola and Trichostrongylidae) were statistically lower than expected; this may be related to: (i) higher tamarin death rate caused by the association; (ii) differences in exposure to helminth infective stages in the various areas of occurrence; (iii) and competition between these helminth species. All helminth species followed a negative binomial distribution, with stronger clumping occurring in Trichostrongylidae and in female GLTs. Distinct transmission strategies of Oncicola sp. and Spiruridae, in contrast with Trichostrongylidae, may partially explain the different clumping levels of these helminths in GLTs. Mean fecal egg counts of all helminths were not different between GLT sexes, ages or areas of occurrence. The three most common helminth species may be a threat to isolated or dense GLT populations.

Prevalence of enteric parasites in pet macaques in Sulawesi, Indonesia

On the Indonesian island of Sulawesi, nonhuman primate pets come into frequent contact with humans, presenting the possibility of zoonotic and anthropozoonotic disease transmission. We collected fecal samples from 88 pet macaques representing six of the seven macaque species currently recognized as endemic to Sulawesi (Macaca nigra, M. nigrescens, M. hecki, M. tonkeana, M. maura, and M. ochreata) as well as two non-endemic species (M. fascicularis and M. nemestrina) in order to determine the prevalence of intestinal parasitic infection in this population. Seven taxa of intestinal protozoa (Blastocystis hominis, Iodamoeba bütschlii, Entamoeba coli, Entamoeba hartmanni, Chilomastrix mesnili, Endolimax nana, and Retortamonas intestinalis) and three taxa of nematodes (hookworm, Trichuris spp., and Ascaris spp.) were detected. The overall parasitization rate was 59.1%. Commensal organisms predominated in this population. Parasitization was not statistically correlated with macaque age group, sex, species, or location, or with the owner's level of education. These findings are discussed in the context of primate pet ownership practices in Sulawesi.

Gastric amebiasis due to Entamoeba histolytica in a Dama wallaby (Macropus eugenii)

A 1.5-year-old captive female Dama wallaby (Macropus eugenii) died after a 3-month period of progressive weight loss, anorexia, bloat, and diarrhea. Histopathologic examination revealed numerous Entamoeba histolytica trophozoites within the gastric mucosa and, less frequently, gastric submucosa and submucosal vessels. Immunofluorescent antibody testing confirmed the identity of the trophozoites as E. histolytica. The trophozoites were associated with mild glandular epithelial necrosis, mucosal erosions, and lymphoplasmacytic inflammation. E. histolytica most commonly causes necrotizing and ulcerative colitis in humans and captive nonhuman primates, and it causes necrotizing and ulcerative gastritis in nonhuman primates with sacculated stomachs adapted for leaf fermentation. Rare cases of gastric amebiasis also have been been reported in captive macropods, which also have complex sacculated stomachs. To our knowledge, this is the first report confirming E. histolytica as the cause of gastric amebiasis in a wallaby. The zoonotic potential of this infection in macropods is uncertain.

Digestive System 1

This chapter deals with the digestive system. The major and minor salivary glands and their secretions also represent and integral part of the protective mechanism of the oral cavity, and derangement of saliva production may lead to loss of integrity of the oral mucosa. Drug-induced abnormalities of taste sensation are also well-described phenomena occurring in man although human studies are necessary for the detection of these effects. Inflammation of the oral cavity may involve the buccal mucosa, the gingiva (gingivitis), the tongue (glossitis), and the peridontal tissues (peridontitis). Therapeutic agents can induce inflammatory lesions in the tongue. Moreover, a protective layer of mucus, a visco-elastic material containing high molecular weight glycoproteins produced by the major and minor salivary glands, covers the stratified squamous mucosa of the oral cavity. Salivary secretions also possess digestive enzyme activity although in herbivores and carnivores, it is usually low in contrast to high digestive enzyme activity in omnivorous species.