ABSTRACT
Infectious and parasitic diseases in zoo animals affect their welfare, reproduction and longevity and pose health threat to researchers, visitors and staff of zoological garden. The aim of this study was to assess biosecurity and determine occurrence of Salmonellae, ecto-and gastro-intestinal parasites (GIP) in Kano zoological garden, Nigeria (KZG). A total of 388 samples were collected from 161 wild animals by non-random sampling method. The distribution of the samples was: one hundred and eleven cloacal swabs from wild birds; one hundred and seventy faecal samples from carnivores (28), herbivores (62), non-human primates (35) and wild birds (45); one hundred and seven ectoparasite (EP) samples from herbivores (2), carnivores (53), non-human primates (27) and wild birds (25). Conventional biochemical tests were used to identify Salmonella species after which suspected/confirmed isolates were subjected to antimicrobial sensitivity test using a panel of 12 antimicrobial agents. Simple flotation technique and microscopic examination methods were used to identify gastro-intestinal parasite eggs/oocysts and ecto-parasites respectively. Of the total faecal and rectal swab samples (196) examined for Salmonella, seven isolates (3.57%) were confirmed; two were from lions (Panthera leo), one each from bush buck (Tragalophus scriptus), Cape eland (Tragalophus oryx), Egyptian geese (Alopochen aegyptiacus), parrot (Psittacus erithacus) and crested porcupine (Hystrix cristata) respectively. The occurrence of Salmonella was 7.14% in carnivores, 5.76% in herbivores and 2.7% in wild birds while the overall occurrence in KZG was 4.8%. All the Salmonella isolates (100%) showed multidrug-resistance (MDR) pattern with resistance profile of 3-4. However, none of the isolates showed mild, extensive or pan drug resistance. Eggs and oocysts were identified from 85 faecal samples: Ascaris from tortoise; Enterobius from chimpanzee; Strongyle from tantalus, red patas and tortoise; Taenia from lion; Toxocara from lion, Nubian vulture and mangoose; Trichurid from baboon, buffalo, porcupine, red patas and tantalus; Coccidia from peacock and red patas; and Isospora from lion and mangoose. The occurrence of GIP egg was highest among non-human primates (37%) and lowest among wild birds (13.5%). Among herbivores, the occurrence was 26.9% while in carnivores was 14.28%. The gastro-intestinal parasite richness count (GIPRC) among carnivores, herbivores, non-human primates and wild birds was 5/3, 5/3, 7/4 and 4/2 respectively. The overall occurrence of GIP eggs and oocysts in KZG was 63% and GIPRC was 21/8. Bug (Cimex lectularius) was identified from baboon and red patas; and Rhipicephalus sanguineus tick from buffalo and common jackal. The occurrence of EP and ecto-parasite richness count (EPRC) among buffalos, common jackal, baboon, red patas and spotted eagle owl were 100% and 2/3; 33% and 2/3; 25% and 1/3; 16% and 2/3; 20% and 1/3 respectively. Of the nine components of zoo biosecurity assessed in KZG, quarantine practices had highest biosecurity risk (100%) and risk level (2.6) while work and hygiene practices for staff and visitors poses lowest biosecurity risk of 58.3% and risk level of 2.0. Audit and validation of biosecurity practices in property management and wildlife sections revealed breaches in traffic control, isolation and sanitation in many sections (70%) of KZG.
1.0 INTRODUCTION
1.1 Background to the Study
Infectious disease within zoo collection impacts on individual health and welfare, and can have long term impacts on reproduction, longevity, behaviours, population and species viability (Reiss and Woods, 2011). Subclinical and chronic diseases can exert their effects for years and even decades. Sickness, death and reproductive failure in collection animals leads to greater costs (husbandry, veterinary care, acquisition), and reduces the financial viability of the zoo as a business. Infectious diseases like salmonellosis that may spread to humans or domestic animals can have serious social, economic and ethical costs (Reiss and Woods, 2011). Salmonellosis is caused by Salmonella species and characterized clinically by one or more of three major syndromes: septicaemia, acute and chronic enteritis (Kahn and Line, 2005). The portal of infection in Salmonellosis is almost always the mouth, so that the severity of the disease in an individual or of an outbreak in a group depends on the degree of contamination and environmental conditions; temperature and dryness, which determine the survival time of Salmonellae (Radostits, 1997). The response to infection with Salmonella varies depending on the size of the challenging dose and the immunological status of the animal (Radostits, 1997).
Parasitism is an important environmental component of the life cycle of most organisms including birds and wildlife (Loye and Zuke, 1991). While ecto-parasites live on the surface of the host‟s body, endo-parasites are found within the body of the host (Narula, 2013). Helminth parasites like Trichuris and Strongyle are significant pathogens of wildlife and responsible for unthriftness, decrease in fecundity rates and sometimes death (Davies and Anderson, 2004). Overcrowding, dampness and unsanitary conditions are the predisposing factors for the proliferation of helminthosis and infectious diseases (Radostits, 1997). Such adverse conditions occur frequently under captivity than under free-living conditions (Devos and Lambrechts, 2003). Helminthes are the predominant macro parasites found in birds and with heavy infestations they cause morbidity and mortality in wild birds (Norton and Ruff, 1997). Single and mixed infestation of mites and nematodes has also been reported in a variety of wild animals kept in captivity for long periods (Mbaya, 2006). Young animals and those stressed by translocation, disease or injury are the most likely to be affected by parasites (Mbaya, 2006; Mbaya et al, 2007).
Biosecurity is the set of precautions taken to minimize the risk of introducing and establishing infectious and parasitic diseases into animal population (Reiss and Woods, 2011). Good zoo biosecurity help keep zoo animals, zoo staff and visitors safe and healthy, minimize costs of treatment, keep zoos open and running during infectious disease outbreak, promote the good reputation of individual zoo and assist zoos in acquiring and managing exotic species (Reiss and Woods, 2011). A zoo‟s ability to protect itself from a disease outbreak will be greatly improved if it has appropriate biosecurity arrangements (Reiss and Woods, 2011).
1.2 Statement of Research Problem
Wildlife are reservoirs of diseases that affect other animals and humans and in many cases animals in captivity are not screened for such diseases. Most veterinary schools in Nigeria do not offer wildlife medicine as a specialty area; this impacts negatively on wildlife health in zoological gardens, wildlife parks, game reserves and other animal sanctuaries. Due to shortage of funding some zoos lack adequate treatment and facilities, do not employ veterinarians as staff while some do not offer professional training on wildlife disease management.
Captive wild birds carry pathogens that may not result in disease in the wild, but once taken into captivity and exposed to a number of stress factors, resistance is lowered and disease can break-out (Schmid, 2005). The removal of wild birds from their natural habitat has had a hugely detrimental impact on the population of many species (Beissinger, 2001). Many species of captive – reared birds, aquatic species and other captive collections commonly become infected with Salmonellae and die from salmonellosis in zoological gardens (Friend, 2001). Game birds such as grouse and pheasants reared in captivity for sporting purposes and cranes for species conservation are often victims of salmonellosis (Friend, 2001). Free-flying birds rarely manifest clinical diseases and may frequently serve as reservoirs of many parasite species (Fallis and Benneth, 1960; Levine, 1963; Carlton and Herman, 1970; Herman and Brischoff, 1994; Mbaya, 2006; Oladele et al, 2012).
1.3 Justification of the Study
Paucity of information regarding wildlife diseases in KZG and Nigeria justifies this research. Zoo visitors interact with captive and free–range wild birds while eating, drinking and sitting thus creating a favourable condition for the spread of infectious agents. Wildlife plays a key role by providing a „zoonotic pool‟ from which new diseases may emerge (Deszak, 2000). Emergence of key zoonotic diseases such as Ebola from wildlife populations has also increased awareness worldwide of the importance of the study of captive wildlife diseases in protecting both livestock and public health (Embrey et al., 2012). Presence of free–range wild birds scavenging on animal feed in KZG and unruly behaviour of some visitors who offer toys and feed to animals poses a serious biosecurity breach. Lack of proper understanding of biosecurity and negligence of some zoo keepers who violate hygiene procedures could also facilitate disease transmission in zoological gardens. Treatment and control measures against parasitic diseases are carried out on regular basis in KZG but baseline data to evaluate the success or failure of the program is not available. Also, the impact of biosecurity practices on the health status of wildlife in KZG is not assessed. A comprehensive study of parasitic and infectious diseases in captive wildlife would aid in the development of possible control measures which may help in enhancing their conservation, survival and performance in captivity. For more than forty years KZG has served as recreational, educational and tourist destination with average of 250,000 – 300,000 visitors annually (KAZOWMA, 1972). Additionally, description of parasites and diseases in free-living and captive animals may help to evaluate the importance of host-parasite relationship in each environment (Carlton and Hermen, 1970). Each zoo‟s unique characteristics will influence its biosecurity requirements and individual zoos are encouraged to develop their own biosecurity plan (Reiss and Woods, 2011). Biosecurity is the best approach for preventing the spread of diseases in zoos; within wildlife, between wildlife and humans or vice-versa. The last outbreak of Ebola triggered donation of several wildlife to KZG raising concern over the health status of wildlife in KZG.
1.4 Aim of the Study
The aim of the study was to assess biosecurity and to determine the occurrence of Salmonella species, ecto- and gastro-intestinal parasites in wildlife in KZG.
1.5 Objectives of the Study
The objectives of the study were to:
- Conduct an assessment of biosecurity practices observed in KZG. xxiii
- Isolate and characterize by biochemical means, Salmonella species from wildlife in KZG.
- Determine antimicrobial resistance of Salmonella species from wildlife in KZG.
- Collect and identify ecto- and gastro-intestinal parasites from wildlife in KZG.
1.6 Research Questions
- What is the level of biosecurity measures observed in KZG?
- Are there Salmonella species infecting wildlife in KZG?
- What is the antimicrobial resistance profile of Salmonella species from wildlife in KZG?
- What is the occurrence of ecto- and gastro-intestinal parasites in wildlife in KZG?
