Frequency of parasites and Salmonella infection in captive maned-wolf, Chrysocyon brachyurus, kept in Zoos at the State of São Paulo, Brazil

Freqüência de parasitas e infecção por Salmonella em lobos guará, Chrysocyon brachyurus, mantidos em zoológicos no Estado de São Paulo

Frequency of parasites and Salmonella infection in captive maned-wolf, Chrysocyon brachyurus, kept in Zoos at the State of São Paulo, Brazil

[Freqüência de parasitas e infecção por Salmonella em lobos guará, Chrysocyon brachyurus, mantidos em zoológicos no Estado de São Paulo]

R. Gilioli, F.A. Silva

Centro de Bioterismo (Cemib) - Unicamp

Caixa Postal 6095

13.083-970-Campinas, SP

Recebido para publicação, em 20 de outubro de 1999.

E-mail: [e-mail]

ABSTRACT

Thirty-one captive maned wolves (Chrysocyon brachyurus, Illiger 1815) from 11 Zoos at the State of São Paulo, Brazil, were screened to investigate the presence of parasites and Salmonella infection by parasitological diagnostic methods and fecal selective culture. The most frequent ecto and endoparasites found were Ctenocephalides felis (56.2%), Rhipicephalus sanguineus (12.5%), Ancylostoma caninum (45.1%), Strongyloides sp. (29.0%), Uncinaria stenocephala (3.2%), Capillaria sp. (3.2%), Entamoeba sp. (22.9%), Sarcocystis sp. (29.0%), Cryptosporidium sp. (19.3%), Eimeria sp. (19.3%), Giardia sp. (9.6%) and Isospora sp. (3.2%). Four different serotypes of Salmonella were identified in six animals (25%). Only one infected animal showed clinical signs of diarrhea. The ability to harbor Salmonella spp. as normal nonpathogenic bacteria of the gastrointestinal tract may be a physiological adaptation of this specie.

Keywords: Maned-wolf, Chrysocyon brachyurus, parasite, Salmonella spp., zoo

RESUMO

Trinta e um lobos guará (Chrysocyon brachyurus, Illiger 1815), mantidos em 11 zoológicos no Estado de São Paulo, foram estudados para verificar a presença de parasitas e de infecção por Salmonella usando-se métodos de diagnóstico parasitológico e cultura seletiva de fezes. Os ecto e endoparasitas encontrados foram: Ctenocephalides felis (56,2%), Rhipicephalus sanguineus (12,5%), Ancylostoma caninum (45,1%), Strongyloides sp. (29,0%), Uncinaria stenocephala (3,2%), Capillaria sp. (3,2%), Entamoeba sp. (22,9%), Sarcocystis sp. (29,0%), Cryptosporidium sp. (19,3%), Eimeria sp. (19,3%), Giardia sp. (9,6%) e Isospora sp. (3,2%). Seis animais apresentaram infecção por Salmonella e quatro diferentes sorotipos foram identificados. Somente um animal apresentava quadro de diarréia sugerindo que a capacidade de portar Salmonella spp. como flora gastrintestinal não patogênica parece ser uma adaptação fisiológica dessa espécie animal.

Palavras-chave: Lobo guará, Chrysocyon brachyurus, parasito, Salmonella sp., zoológico

INTRODUCTION

The maned-wolf (Chrysocyon brackyurus) also called Brazilian wolf or lobo guara is the largest and finest canine of Brazilian fauna. This species is very vulnerable due to destruction of great part of its natural habitat and to killing by people who considerate it a threat to domestic animals which are usually kept free and without nocturnal shelter. It can be found in just a few Zoos of Brazil and very little is known about its way of life due to the fact that this animal does not thrive in captivity (Dietz, 1984; Carvalho & Vasconcelos, 1995).

Captive and free wolves suffer from several bacterial and viral illnesses and parasitic infections. Some maladies they bring from the wild habitat and others they get during transportation or captive maintenance. Those captive animals that do not die during the adaptation period to captivity succumb to a common disease provoked by stress and multiple parasitism (Fletcher et al., 1979; Mundin et al., 1991; Carvalho & Vasconcelos, 1995). There are several reports of parasites and Salmonella sp. infection in wild and captive species kept in Zoos including crocodile, rhinoceros, elephant, exotic felines, raptors and rodents (Ocholi & Enurah, 1989; Clyde et al., 1997; Kenny et al., 1997). Possible sources of infection at the Zoos are raw feed, native rodents and wild birds that have access to cages (Loureiro, 1985; Davis & Wray, 1997). Not only is salmonellosis of veterinary importance, but it is a significant zoonotic disease (Friedman et al., 1998).

The present investigation is result of a special program supported by the Sociedade Paulista de Zoológicos, developed with the purpose to know about the health status of captive Brazilian wolf (lobo guara).

MATERIAL AND METHODS

This investigation has focused on 11 animal facilities and detailed clinical examinations and biometric analysis of the animals were conducted. Samples of blood, urine, and feces were submitted for hematological, hematochemical, serological, microbiological and parasitological examinations.

The immobilization of the animals was carried out by anesthesia with IM injection of 10 mg/kg of ketamine hydrocloridrate 50 plus 1 mg/kg of xylacine (Happyvet, Rompun-Bayer), injected by syringes through a blowpipe.

After animal immobilization, ectoparasites were collected in 70% (v/v) ethanol, clarified five days in 10% (w/v) KOH solution and submitted to microscopic identification. Fresh fecal samples were collected from the rectum using a swab wooden stick, then placed directly in tubes, and kept refrigerated. One portion of the feces was mixed with 10% neutral buffered formalin for preservation and another portion was immediately submitted to parasitological and microbiological examination.

A feces suspension was made using physiological saline solution, and it was kept warm on a heating plate for preservation of the larval and adult worms, and the motility of trophozoites. Helminth and protozoan parasites were detected by direct microscopic examination, and by methods of parasite concentration (Willis, 1921; Sheather, 1923; Hoffman et al., 1934; Faust et al., 1938). Protozoan cysts were stained with Lugol iodine solution for easier identification. Fecal smears were fixed in methanol-3% (v/v) in HCl solution and stained by modified Ziehl-Neelsen method to detect oocyts of Cryptosporidium spp. (Henriksen & Pohlenz, 1981). Sporulation of coccidia oocysts was performed by mixing feces with an equal volume of 2.5% (w/v) potassium dichromate solution stored at room temperature and, hatching of helminth eggs was carried out by culturing feces in granulated charcoal (Hoffman, 1987).

Laboratory procedures for Salmonella spp. isolation followed previously described protocols (Edwards & Ewing, 1972; Valada, 1988). Some 1cm³ pieces of feces were placed into tubes containing 10ml of glicerol broth, selenite-cystine broth (Difco Laboratories, Detroit, Michigan, USA®) and tetrathionate broth (BBL/Becton Dickinson & Co, Cockeysville, MD 21030, USA®), followed by overnight incubation at 37ºC and subculture in Mac Conkey agar and SS agar². Isolated colonies were tested on modified triple sugar iron adapted by Rugai-Araujo, and then identified by biochemical tests. Those with characteristics of Salmonella were further identified using O polyvalent antiserum containing groups A-E, Vi, and H polyvalent antiserum containing groups a-d, i, 1, 2, 5 (Probac. Produtos Bacteriologicos Ltda., São Paulo, Brazil®). Serotyping was performed by the Sector of Bacteriology of the Adolfo Lutz Institute, São Paulo, Brazil.

RESULTS AND DISCUSSION

Thirty-one adult maned wolves (15 female and 16 male) were screened by ecto and endoparasites, and Salmonella infection. Parasite infections were detected in every facility tested. The results are shown in Table 1.

Salmonella was isolated in six of 24 tested animals and four distinct serotyping were identified. Enteric bacteria other than Salmonella sp. also were isolated from fecal cultures and the results are shown in Table 2.

The maned wolves are omnivorous and their diets in the captivity are composed by uncooked or unprocessed foods such as fruits, vegetables, pelletized ration, chicken eggs, and raw meat-based diet (meat and bone, fish, chicken-neck and viscera). These foodstuffs can be source of contamination by Salmonella spp. and some of the detected endoparasites. Native rodents, water and droppings of wild birds that have access to pens also can be sources of infections (Loureiro, 1985; Tablante Jr. & Lane, 1989; Davis & Wray, 1997).

Despite the balanced diet, the parasites detected in this research can alter the health status of the animals by inducing physiological and immunological alterations, stimulating abnormal tissue growth, inducing tissue damage, competing for nutrients, decreasing the volume of blood and body fluids, and by mechanical interference (Hsu, 1980).

Some parasites with zoonotic potential, such as Cryptosporidium sp., Eimeria sp., Isospora sp., Giardia sp., Sarcocystis sp., Ancylostoma caninum, and Strongyloides sp. can be a threat to people and other animal species that have contact with them. Cryptosporidium oocysts can stay active for a long time, and are very resistant to environmental conditions and chemical treatment. Chlorine does not kill this microorganism (Dennen, 1998).

Cryptosporidium sp. has gained more recognition over the last decade as an enteropathogen in a wide variety of host animals. Recent studies have revealed that this organism is more prevalent and pathogenic than previously thought. Infections producing clinical diseases have been recorded in numerous host species including humans, and the organism is now regarded as an emergent zoonosis. Imunossupressed and weakling animals are more susceptible to infection and clinical illness (O’Donoghue, 1985; Current & Garcia, 1991).

Salmonella organisms are ubiquitous in nature and common environmental and aquatic contaminants. It has been recovered from cultures of crude diets and high percentage of food products of animal origin have been estimated to be contaminated with Salmonella (Davies & Wray, 1997).

Clinical syndromes of salnonellosis include enteritis or septicemia, which can be an acute or chronic process. Young, old, immunossuppressed and stressed animals are more susceptible to clinical salmonellosis (Morse, 1980; Howard, 1993; Battisti et al., 1998). However, only one screened animal had clinical signs of illness. The incidence of fecal shedding of Salmonella sp. among health maned wolves suggests that these organisms can be maintained as a component of the normal flora in immunocompetent animals. Frequent ingestion of this microorganism might be a reason for physiological adaptation of maned wolf as a host for Salmonella.

Due to the increase of resistance to drugs, the antimicrobial treatment of salmonellosis is indicated only in severe systemic or invasive infections (Timoney et al., 1988; Greene, 1990).

All zoo employees having contact with maned-wolf feces and raw diets should be informed of their occupational risk to zoonotic parasites and Salmonella infections. Appropriate precautions should be taken to prevent spread of this microorganism, since salmonellosis is an important zoonosis, in addition to its veterinary importance (Friedman et al., 1998).

The number of Salmonella microorganisms is not static and it increases in feces, food and moist exhibits over time. Removal and disposal of uneaten food and feces should be practiced followed by appropriate desinfection of exhibits.

ACKNOWLEDGMENTS

We are grateful for the collaboration and assistance received from Zoos staff for samples collection during management of the animals in captivity. Thanks to the personal envolved in the study of maned-wolf (lobo guará) supported by the Sociedade Paulista de Zoológicos, in special to veterinarians Dr. Marcelo da Silva and Dr. Samario Rodrigues Menezes, to biologists Adriana S. Lobate, Cleyde A.F.S. Chieregatto, Daniele M. Rodrigues, and to the veterinary student Marco A. Bastos da Silva for technical assistance. We also thank Prof Dr. Antonio J.P. Ferreira (FMVZ-USP) for helping with the Salmonella serotyping.

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Publication Dates

• Publication in this collection
  21 Sept 2000
• Date of issue
  Aug 2000

History

• Received
  20 Oct 1999