Heterogeneity in patterns of helminth infections across populations of mountain gorillas (Gorilla beringei beringei)

Conservation efforts have led to the recovery of the endangered mountain gorilla populations. Due to their limited potential for spatial expansion, population densities increased, which may alter the epidemiology of infectious diseases. Recently, clinical gastrointestinal illnesses linked to helminth infections have been recorded in both gorilla populations. To understand drivers and patterns of helminth infections we quantified strongylid and tapeworm infections across both Virunga Massif and Bwindi populations using fecal egg counts. We assessed the impact of age, sex, group size, season and spatial differences used as a proxy, which reflects observed variation in the occurrence of gastrointestinal problems, vegetation types, gorilla subpopulation growth and associated social structure on helminth infections. We revealed striking geographic differences in strongylid infections with higher egg counts mostly in areas with high occurrences of gastrointestinal disease. Increased helminth egg counts were also associated with decreasing group size in some areas. Observed spatial differences may reflect mutual effects of variations in subpopulation growth rates, gorilla social structure, and vegetation associated with altitude across mountain gorilla habitat. Helminth infection intensities in Virunga gorillas were lowest in the youngest and the oldest animals. Elucidating parasite infection patterns of endangered species with low genetic diversity is crucial for their conservation management.

Metastatic perioral melanoma in a wild mountain gorilla (Gorilla beringei beringei)

A 30-year-old free-ranging female mountain gorilla (Gorilla beringei beringei) developed a perioral mass that was surgically debulked and diagnosed as malignant melanoma. After tumor recurrence, a canine melanoma vaccine was administered. However, the gorilla died shortly thereafter, and metastases to lymph nodes, lung, liver, and kidney were found post-mortem.

Unlocking the Role of a Genital Herpesvirus, Otarine Herpesvirus 1, in California Sea Lion Cervical Cancer

Urogenital carcinoma in California sea lions (Zalophus californianus) is the most common cancer of marine mammals. Primary tumors occur in the cervix, vagina, penis, or prepuce and aggressively metastasize resulting in death. This cancer has been strongly associated with a sexually transmitted herpesvirus, otarine herpesvirus 1 (OtHV1), but the virus has been detected in genital tracts of sea lions without cancer and a causative link has not been established. To determine if OtHV1 has a role in causing urogenital carcinoma we sequenced the viral genome, quantified viral load from cervical tissue from sea lions with (n = 95) and without (n = 163) urogenital carcinoma, and measured viral mRNA expression using in situ mRNA hybridization (Basescope®) to quantify and identify the location of OtHV1 mRNA expression. Of the 95 sea lions diagnosed with urogenital carcinoma, 100% were qPCR positive for OtHV1, and 36% of the sea lions with a normal cervix were positive for the virus. The non-cancer OtHV1 positive cases had significantly lower viral loads in their cervix compared to the cervices from sea lions with urogenital carcinoma. The OtHV1 genome had several genes similar to the known oncogenes, and RNA in situ hybridization demonstrated high OtHV1 mRNA expression within the carcinoma lesions but not in normal cervical epithelium. The high viral loads, high mRNA expression of OtHV1 in the cervical tumors, and the presence of suspected OtHV1 oncogenes support the hypothesis that OtHV1 plays a significant role in the development of sea lion urogenital carcinoma.

Is plastic ingestion in birds as toxic as we think? Insights from a plastic feeding experiment

Plastic pollution is a modern tragedy of the commons, with hundreds of species affected by society's waste. Birds in particular mistake plastic for prey, and millions of wild birds carry small plastic loads in their stomach and are exposed to potential toxicological effects. It is currently unknown how severely the toxicological and endocrine disrupting chemicals in plastic affect avian development, reproduction and endocrine function. To address this question, we conducted multi-generational plastic feeding experiments to test the toxicological consequences of plastic ingestion at environmentally relevant loads in Japanese quail, Coturnix japonica, investigating parental and two filial generations. Contrary to expectations, we found no evidence of lasting toxicological effects on mortality, adult body weight, organ histology, hormone levels, fertility, hatch rates and eggshell strength in birds experimentally fed plastic. However, we found plastic ingestion causes higher frequencies of male reproductive cysts and minor delays in chick growth and sexual maturity, though without affecting ultimate survival or reproductive output. We report that although plastic ingestion causes detectable endocrine effects in our model species, our lack of finding mortality, morbidity and adverse reproductive outcomes may challenge the common hypothesis of severe toxicological harm and population-level effects when environmentally relevant loads of plastic are ingested.

Central vestibular disease in a blue and gold macaw (Ara ararauna) with cerebral infarction and hemorrhage

A 24-year-old female blue and gold macaw (Ara ararauna) was presented for an acute onset of left head tilt. On examination, the macaw was dehydrated and had a 120-degree left head tilt, decreased proprioception of the left pelvic limb, and intermittent vertical nystagmus. Results of hematologic testing and biochemical analysis revealed severe leukocytosis with lymphopenia and heterophilia and a high uric acid concentration. Radiographs showed bilateral intertarsal joint osteoarthritis and a healed ulnar fracture. Magnetic resonance imaging of the brain revealed focal T2 and fluid-attenuated inversion recovery hyperintense lesions in the right cerebral hemisphere and in the midbrain. The midbrain lesion showed susceptibility artifact on the T2* sequence, suggesting hemorrhage. In the T2* sequence, iron accumulation (as seen with hemorrhage) distorts the magnetic signal, resulting in the production of a susceptibility artifact, which can then be visualized as a region of hypointensity. The bird was hospitalized but died despite intensive care. Necropsy revealed multiple cerebral vascular lesions including an acute cerebral infarct, a ruptured midbrain aneurysm, and multifocal systemic atherosclerosis. To our knowledge, this is the first report of a cerebral aneurysm in a bird. This report correlates the clinical presentation, imaging, and histopathologic findings in a macaw with central vestibular disease and demonstrates how advanced imaging techniques can identify hemorrhagic lesions through the T2* sequence.

Changes in blubber contaminant concentrations in California sea lions (Zalophus californianus) associated with weight loss and gain during rehabilitation

California sea lions have high levels of persistent organic pollutants (POPs) in their blubber. Animals affected by domoic acid fast and refeed during their rehabilitation. We studied the effect of decreases in total body mass (16 +/- 7% of initial body mass) on blubber POP contaminant concentrations and estimated POP burdens during fasting (12 +/- 5 days) in 19 California sea lions. The effect of refeeding (92 +/- 8% of initial body mass) was also investigated. Significant increases in the concentration of all POPs were found over the mass loss period and decreases during mass gain. A basic mass balance model indicated that the changes did not conform to a simple concentrating and diluting pattern and a proportion of the contaminants were lost from the lipid pool. During mass loss, the lower chlorinated polychlorinated biphenyl congeners, chlordanes, and hexachlorocyclohexanes were lost at a higher rate than the other contaminant classes (particularly polybrominated diphenyl ethers). During mass gain the behavior of all contaminant classes was more consistent with the dilution model. These results indicate the importance of considering the energetic contextwhen sampling blubberfor long-term contaminant monitoring and suggest an initial approach to adjust for such differences.

SRY negative 64,XX intersex phenotype in an American saddlebred horse

A female American saddlebred horse was presented for surgical correction of a possible pseudohermaphrodite condition. The horse had abnormal external genitalia and exhibited stallion-like behaviour. No evidence of uterine or ovarian tissue was identified on laparoscopic examination, but hypoplastic testicular-like tissue was removed, although this was found to contain no spermatogonia upon histopathological examination. A karyotype was performed and showed the normal chromosomal complement for a female horse (64,XX). Polymerase chain reaction to detect the SRY gene was negative in peripheral blood as well as the testicular-like tissue. This case represents the first report of an SRY negative XX-male sex reversal intersex phenotype, which is a potentially inherited condition, in an American saddlebred horse.

Aerobic bacterial flora of the vagina and prepuce of California sea lions (Zalophus californianus) and investigation of associations with urogenital carcinoma

To investigate the association between genital bacterial infection and urogenital carcinoma in California sea lions (Zalophus californianus), vaginal and preputial swabs for bacterial isolation were taken from 148 free-ranging and 51 stranded California sea lions including 16 animals with urogenital carcinoma. Cytological examination of vaginal or preputial smears showed a majority (65.5%, 57/87) of animals examined had mild or no inflammation. Aerobic bacteria were isolated from 116 (78.4%) wild sea lions and 100% of stranded animals. A total of 403 isolates were identified representing 51 unique bacterial species. The median number of isolates per animal increased with age in the wild group, but there was no difference in the number of isolates per animal between wild and stranded adults. The most common bacteria isolated from the wild sea lions were Psychrobacter phenylpyruvicus (39 isolates), non-hemolytic Streptococcus (35 isolates), Corynebacterium spp. (30 isolates), and Escherichia coli (20 isolates). More bacterial species were isolated from stranded animals than wild animals (33 versus 26) and there was significantly less growth of P. phenylpyruvicus, Corynebacterium spp., and Moraxella-like spp. in the stranded animals. Beta-hemolytic Streptococcus was the only bacterium significantly associated with urogenital carcinomas in California sea lions, but only in females.

MHC gene configuration variation in geographically disparate populations of California sea lions (Zalophus californianus)

Major histocompatibility complex (MHC) class II DRB genotypes were examined in two geographically isolated populations of California sea lions (Zalophus californianus) (Gulf of California and California coastal Pacific Ocean). Genomic DNA from 227 California sea lions was examined using eight sequence-specific primer (SSP) pairs flanking the putative peptide-binding site. A total of 40 different Zaca-DRB genotype configurations were identified among the 227 individuals. Using SSP-PCR, significant differences were found between coastal California and Gulf of California Zalophus populations in numbers of DRB sequences per individual and configuration of sequences within individuals. Additionally, unique local patterns of MHC diversity were identified among the Midriff Island animals. These population differences are consistent with either ecologically distinct patterns of selection pressures and/or geographical isolation. The consequences of these partitioned MHC configurations at the population level are as yet unknown; however, the worldwide increase in emerging marine diseases lends urgency to their examination.

Evaluation of a collagen patch as a method of enhancing ventriculotomy healing in Japanese quail (Coturnix coturnix japonica)

OBJECTIVE

To assess the ability of a porcine submucosal collagen patch to enhance ventriculotomy healing in quail.

STUDY DESIGN

Histologic assessment of wound repair after ventriculotomy. Animal Population-Eighteen adult Japanese quail.

METHODS

All quail had a ventriculotomy through the caudoventral thin muscle. The quail were randomly assigned to 1 of 2 groups: group I (n = 9) had routine closure and group II (n = 9) had routine closure and the application of a porcine submucosal collagen patch over the serosal surface of the ventricular suture line. Three quail from each group underwent necropsy at 7, 14, and 21 days after surgery and healing of the ventriculotomy site was evaluated by microscopy.

RESULTS

Ventricular mucosal epithelium was completely healed at 21 days postoperatively. Time to restoration of the ventricular submucosal integrity was variable in both groups. There was evidence of a gross or microscopic perforation in 4 quail in group II, which was statistically significant (P =.041). Quail with perforations had significantly elevated numbers of ventricular serosal lymphoid aggregates compared with those without perforations (P =.029). There were no other significant temporal differences between group I and group II for mortality or histopathologic grading of wound healing.

CONCLUSIONS

A porcine collagen patch did not enhance ventriculotomy wound healing. Subjectively, the collagen patch might have contributed to perforation by the generation of a lymphocytic xenograft rejection response.

CLINICAL RELEVANCE

Ventriculotomy can be safely performed using routine closure methods in healthy birds.

Rectal prolapse in a free-ranging mountain gorilla (Gorilla beringei beringei): clinical presentation and surgical management

A juvenile female mountain gorilla (Gorilla beringei beringei) of the Mubare tourist group in Bwindi Impenetrable National Park, Uganda, developed a severe, complete rectal prolapse that did not spontaneously resolve. Eight months prior, a juvenile female mountain gorilla of the Mubare group developed a mild, complete rectal prolapse that resolved spontaneously within 24 hr. Field guides reported that spontaneously resolving prolapses had been seen previously in two other juveniles, one of which was from the Mubare group. The tissue became increasingly necrotic and maggot infested over the course of 1 wk. Surgical intervention involved amputation of the affected rectal tissues and suturing the viable portion to the anal sphincter muscle with simple interrupted absorbable sutures. The surgery was performed in the field in accordance with Uganda Wildlife Authority policies. Antibiotics and anthelmintics were administered systemically, and the gorilla returned to the group. The gorilla appeared to recover fully after 3 wk. Histology of the resected rectal tissue confirmed intense inflammation and necrosis with myiasis but did not reveal an underlying etiology.

Fatty liver hemorrhagic syndrome in hens overfed a purified diet. Selected enzyme activities and liver histology in relation to liver hemorrhage and reproductive performance

A nutritionally adequate, purified diet was developed and used in studies to characterize selected aspects of laying hens in which fatty liver hemorrhagic syndrome (FLHS) was induced by overfeeding. Hens consuming the diet ad libitum or intubated with the diet in quantities equivalent to usual daily energy intake maintained normal rates of lay, did not become obese, and did not develop liver hemorrhage. Overfed hens had a 33% incidence of FLHS, as indicated by the presence of severe liver hemorrhage score, and displayed the full range of symptoms associated with spontaneous outbreaks of FLHS, including definitive lesions of hepatic reticulin. Among four groups of hens clinically classified according to rates of liver hemorrhage and egg production, there were no differences noted in total liver fat, liver fat concentration, or final body weight. Liver hemorrhage was associated with the degree of induction of liver lipogenic accessory enzymes. Serum enzyme activities indicate that overfed hens, unlike the overfed goose, retain hepatocellular membrane integrity. Overfeeding caused altered reproductive performance in 72% of hens. Alterations included erratic laying, increased incidence of double ovulations, shell defects, follicular collapse, and oviduct involution. Pattern of lay preceding necropsy seemed to influence follicle weight at necropsy. The data presented re-emphasize the interdependence among liver, ovary, and oviduct function in the etiology of FLHS.

Pathogenesis of experimentally induced feline immunodeficiency virus infection in cats

Feline immunodeficiency virus (FIV; formerly, feline T-lymphotropic lentivirus) is a typical lentivirus resembling human and simian immunodeficiency viruses in morphologic features, protein structure, and reverse transcriptase enzyme. It is antigenically dissimilar, however. The virus is tropic for primary and permanent feline T-lymphoblastoid cells and Crandell feline kidney cells. The virus did not grow in other permanent feline non-lymphoblastoid cells that were tested, or in lymphoid and non-lymphoid cells from man, dogs, mice, and sheep. During short-term inoculation studies in cats, the feline immunodeficiency-like syndrome found in nature was not experimentally induced, but a distinct primary phase of infection was observed. Fever and neutropenia were observed 4 to 5 weeks after inoculation; fever lasted several days, and neutropenia persisted from 1 to 9 weeks. Generalized lymphadenopathy that persisted for 2 to 9 months appeared at the same time. Antibodies to FIV appeared 2 weeks after inoculation and then plateaued. Virus was reisolated from the blood of all infected cats within 4 to 5 weeks after inoculation and persisted indefinitely in the face of humoral antibody response. Virus was recovered from blood, plasma, CSF and saliva, but not from colostrum or milk. Contact transmission was achieved slowly in one colony of naturally infected cats, but not between experimentally infected and susceptible specific-pathogen-free cats kept together for periods as long as 4 to 14 months. The infection was transmitted readily, however, by parenteral inoculation with blood, plasma, or infective cell culture fluids. In utero and lactogenic transmission were not observed in kittens born to naturally or experimentally infected queens. Lymphadenopathy observed during the initial stage of FIV infection was ascribed to lymphoid hyperplasia and follicular dysplasia. A myeloproliferative disorder was observed in 1 cat with experimentally induced infection.

Oral lesions in rhesus monkeys associated with infection by simian AIDS retrovirus, serotype-I (SRV-1)

Simian acquired immunodeficiency syndrome (SAIDS) is a retrovirus-induced immunodeficiency disease that affects certain nonhuman primates and has many parallels to human AIDS. We examined 72 rhesus monkeys (Macaca mulatta) exposed to SAIDS retrovirus serotype-1 (SRV-1) and 81 healthy control monkeys at the California Primate Research Center to determine the prevalence of oral lesions. At the time of examination, 69 of the 72 monkeys exposed to SRV-1 had serologic and/or virologic evidence of SRV-1 infection. None of the 81 control monkeys had any evidence of infection with SRV-1. Acute necrotizing ulcerative gingivitis (ANUG), oral yeast infections, and noma occurred in 10% (p less than 0.01), 4%, and 1%, respectively, of the study group of 72 animals but were found in none of the control animals. Thus, ANUG occurs rather frequently in rhesus monkeys with evidence of SRV-1 infection. The reproducible immunodeficiency that follows inoculation of SRV-1 in rhesus monkeys promises to be a useful model for studying the pathogenesis of ANUG associated with immunodeficiency.

The causes of false-positives encountered during the screening of old-world primates for antibodies to human and simian retroviruses by ELISA

Sera from 526 old-world primates representing 50 different species were screened by ELISA for antibodies to human T-lymphotropic viruses I and III, and simian retrovirus type 1 (SRV-1). About one-fourth of the sera were positive by ELISA. There was a tendency, however, for the same sera to be positive for all three human and simian retroviruses. Only about one in five of the ELISA antibody-positive sera were confirmed to be positive by Western blotting. False-positive ELISA antibody tests were particularly common among sera from mandrills, crab-eating macaques, lion-tailed macaques, African green monkeys, and DeBrazza's and moustached guenons. Sera that were falsely positive in ELISA antibody tests to the three human and simian retroviruses were found to contain antibodies that reacted at comparable intensity with feline leukemia, infectious peritonitis and panleukopenia viruses. The false anti-viral activity of these sera was found to be due to antibodies that reacted with non-viral proteins that were copurified with all five virus preparations. These proteins were present in normal cat and human cells used to grow the various viruses and in gelatin. The implications of nonspecific cell-protein antibodies in primate sera were discussed in the light of this and previous seroepidemiologic studies of man and old-world monkeys.

Hematologic abnormalities in simian acquired immune deficiency syndrome

Hematologic abnormalities were defined in 31 rhesus monkeys (Macaca mulatta) with simian acquired immune deficiency syndrome (SAIDS). Animals manifested anemia (hypochromic/microcytic), severe neutropenia and progressive lymphopenia, monocytosis and occasional thrombocytopenia. Bone marrow studies showed erythroid hyperplasia with a marked left shift and adequate megakaryocytes. Two animals showed profound hypoplasia of all hematopoietic elements. Most animals were iron deficient, but the course of the anemia suggested additional factors. There was no evidence of immune hemolysis. The pathogenesis of these abnormalities is not clear and will require further study. This reproducible disease will allow studies to elucidate the mechanisms of viral-induced hematologic abnormalities.