Visceral and presumptive neural baylisascariasis in an orangutan (Pongo pygmaeus)

MANAGEMENT OF MEDICAL COMPLICATIONS ASSOCIATED WITH A PRESUMED TETANUS INFECTION IN A NORTHWEST BORNEAN ORANGUTAN (PONGO PYGMAEUS PYGMAEUS)

An 18-yr-old female orangutan (Pongo pygmaeus pygmaeus) developed opisthotonus after sustaining conspecific bite wounds 3 wk earlier. The orangutan developed progressive tetraparesis and dysphagia, despite normal mentation, suggestive of tetanus. A tetanus vaccine had been administered at 2 yr of age, but none since. Brain magnetic resonance imaging, computed tomography, cerebral spinal fluid tap, and bloodwork were unremarkable. Viral, Baylisascaris, and tetanus toxin testing were negative. A femoral central venous catheter (CVC) was placed to provide medications, fluids, and parenteral nutrition. The orangutan received human tetanus immunoglobulin, tetanus toxoid, penicillin, methocarbamol, and analgesia. After 1 wk, the catheterized limb became edematous; a deep vein thrombosis (DVT) was diagnosed ultrasonographically. A cephalic CVC was placed, the limb casted, intravenous therapy reinitiated, and enoxaparin started. The orangutan became mobile days later, and progressively improved. Despite no compliance with enoxaparin, the DVT resolved without residual signs. This is the first reported case of presumptive tetanus and DVT in a great ape.

Parasites of orangutans (primates: ponginae): An overview

Wild orangutan populations exist in an increasingly fragile state. As numbers continue to decline and populations became fragmented, the overall health of remaining individuals becomes increasingly at risk. Parasitic infections can have a serious impact on the health of wild orangutans, and can be fatal. It has been reported that rehabilitated individuals demonstrate a higher prevalence of parasitic diseases, and it is possible that they may spread these infections to wild orangutans upon reintroduction. In order to ensure the success of reintroduction and conservation efforts, it is crucial to understand the potential risks by fully understanding what parasites they have been reported to be infected with. Using this knowledge, future conservation strategies can be adapted to minimize the risk and prevalence of parasite transmission in the remaining orangutan populations. There is still limited information available on orangutan parasites, with several still not identified to the species level. Based on comprehensive literature review, we found 51 parasite taxa known to infect wild, semi-wild, and captive orangutans, including newly reported species. Here, we summarize methods used to identify parasites and draw conclusions relative to their reported prevalence. We also recommend fecal sample preservation and analytical methods to obtain best result in the future.

HEALTH SURVEY OF FREE-RANGING RACCOONS (PROCYON LOTOR) IN CENTRAL PARK, NEW YORK, NEW YORK, USA: IMPLICATIONS FOR HUMAN AND DOMESTIC ANIMAL HEALTH

We conducted health assessments on 113 free-ranging raccoons ( Procyon lotor ) in Central Park, New York City, US, in February 2010, September 2010, and November 2011 in conjunction with a trap-vaccinate-release program to control a raccoon rabies epizootic. Five individuals were sampled at two time points for 118 raccoon examinations in total. We tested 13 of 13 and 8 of 13 euthanized raccoons for rabies and canine distemper virus (CDV), respectively, by antigen testing on brain tissue; all were negative for both viruses. Endoparasitism was the most common necropsy finding, with definitive identification of Baylisascaris procyonis in six of eight (75%) necropsied raccoons. Multiple intestinal parasites were detected in feces of living raccoons, including ascarid-type ova in 25 of 80 (31%) raccoons, with B. procyonis confirmed in one sample. Median blood lead level was 7.3 μg/dL (n=104). Rabies virus neutralizing antibody titer was ≥0.5 IU/mL in 9 of 88 (10%) raccoons naive to rabies vaccination and in 13 of 20 (65%) previously vaccinated raccoons. The majority of raccoons we tested were seropositive for canine parvovirus-2 (54/59, 92%) and Toxoplasma gondii (39/60, 65%). Fewer were seropositive for Rickettsia rickettsii (3/30, 10%). None were seropositive for CDV (n=108), canine adenovirus-1 (n=60), or Borrelia burgdorferi (n=30). Ectoparasites found during 16 of 118 (13.6%) physical examinations included Ixodes texanus ticks (15/118, 12.7%) and Trichodectes octomaculatus lice (1/118, 0.8%). We detected Campylobacter jejuni in 5 of 79 (6%) fecal samples. We detected 11 Salmonella enterica serotypes in 70 of 111 (63.1%) enteric cultures, the most common of which were Salmonella Newport (20/70, 29%) and Salmonella Oranienburg (20/70, 29%). These results indicate that raccoons in Central Park likely are involved in the environmental occurrence and potential disease transmission of a variety of infectious and noninfectious diseases of concern for human, wildlife, and domestic animal health.

Update on Baylisascariasis, a Highly Pathogenic Zoonotic Infection

Baylisascaris procyonis, the raccoon roundworm, infects a wide range of vertebrate animals, including humans, in which it causes a particularly severe type of larva migrans. It is an important cause of severe neurologic disease (neural larva migrans [NLM]) but also causes ocular disease (OLM; diffuse unilateral subacute neuroretinitis [DUSN]), visceral larva migrans (VLM), and covert/asymptomatic infections. B. procyonis is common and widespread in raccoons, and there is increasing recognition of human disease, making a clinical consideration of baylisascariasis important. This review provides an update for this disease, especially its clinical relevance and diagnosis, and summarizes the clinical cases of human NLM and VLM known to date. Most diagnosed patients have been young children less than 2 years of age, although the number of older patients diagnosed in recent years has been increasing. The recent development of recombinant antigen-based serodiagnostic assays has aided greatly in the early diagnosis of this infection. Patients recovering with fewer severe sequelae have been reported in recent years, reinforcing the current recommendation that early treatment with albendazole and corticosteroids should be initiated at the earliest suspicion of baylisascariasis. Considering the seriousness of this zoonotic infection, greater public and medical awareness is critical for the prevention and early treatment of human cases.

Cerebral Baylisascaris larva migrans in a cynomolgus macaque (Macaca fascicularis)

An incidental, asymptomatic, focal inflammatory lesion was detected in brain cerebrum of an approximately 6-year-old, female cynomolgus macaque from a chronic toxicology study. No gross lesions were noted at necropsy. Microscopically, the lesion contained a cross-section of larvae approximately 70-80 μm in diameter, a centrally located intestine flanked on either side by large triangular excretory columns, and prominent single lateral cuticular alae. Mixed inflammatory cells of eosinophils, macrophages, and lymphocytes admixed with abundant connective tissue stroma and necrosis surrounded the larvae. Histochemical stains for trichrome revealed significant amount of fibrous connective tissue. The morphology of the larvae was compatible with Baylisascaris spp. Based on the microscopic and histochemical examination, a diagnosis of neural Baylisascaris spp. larva migrans was made.

Parasites and the conservation of small populations: The case of Baylisascaris procyonis

Human demands on natural resources result in landscape changes that facilitate the emergence of disease. Most emerging diseases are zoonotic, and some of these pathogens play a role in the decline of vulnerable wildlife species. Baylisascaris procyonis, the common roundworm parasite of raccoons (Procyon lotor), is a well recognized zoonotic infection that has many of the properties associated with a pathogen capable of driving extinction. It is highly non-specific and frequently pathogenic with regard to paratenic hosts, which contact eggs of B. procyonis at raccoon latrines. Eggs accumulate at latrines and remain viable for many years. Transmission of B. procyonis is sensitive to changes in land-use, and fragmented habitats increase contact rates between raccoons, potential paratenic hosts, and the parasite. Raccoons, and subsequently B. procyonis, have been introduced to Europe and Japan, where naïve vertebrates may be exposed to the parasite. Finally, domestic animals and exotic pets can carry patent infections with B. procyonis, thus increasing environmental contamination beyond raccoon latrines, and expanding the area of risk to potential paratenic hosts. This parasite can potentially contribute to extinctions of vulnerable species, as exemplified by the case of the Allegheny woodrat (Neotoma magister), a species that has experienced local declines and extinctions that are linked to B. procyonis. Conservation strategies for vulnerable species should consider the transmission ecology of parasitic pathogens, like B. procyonis.