Helminth parasites and reservoir status of captive wild

Aim: To determine the various helminth parasites and associated helminth reservoir status of captive wild ruminants in the semi-arid region of north-eastern, Nigeria. Materials and Methods: Faecal samples were examined for nematode ova by the simple floatation technique using saturated sodium chloride solution as floatation medium. Trematode eggs were examined by the sedementation technique. The modified McMaster technique was used to determine the intensity of helminth infections among the various species of wild ruminants examined, while larval isolation and identification using the modified Baerman's technique was used to determine the various species of parasites encountered. Results: Out of the 36 samples examined, a high parasite count due to Strongyle infection without the manifestation of overt clinical signs was observed among the captive wild ruminants. The egg counts ranged from 500 + 10.0 among the Grimm's duicker (Sylvicaprea grimmia) to 5, 350 + 51.70 among the Senegal hartebeest (Damaliscus korrigum). The helminth larvae recovered which were common to all the species of wild ruminants were those of Haemonchus contortus, Trichostrogylus axei and Strongyloides papillosus, Demographic data such as age, sex and species of wild animals showed no significant (p>0.05) variation on the prevalence of the helminth infections. Conclusion: The results of this study suggests that the captive wild ruminants in the semi-arid region of north-eastern, Nigeria, were reservoirs of various helminth parasites of medical and veterinary importance. It was therefore, recommended that improved sanitary conditions in animal enclosures, regular and strategic anthelmintic medications may on one hand protect the spread of infection to attendants and visitors to the park. On the other hand it will enhance the in-situ conservation of the rare and endangered species of wild ruminants in the area.


Introduction
have also been conducted [8,9] at the Kainji Lake National Park in central Nigeria, and at Maiduguri zoo Many cases of resistance to helminth infections [10,11]. in wildlife often breakdown when they are translocated Helminth parasites are significant pathogens of from their natural habitat to the unnatural conditions as wildlife and are responsible for unthriftness, decrease obtained in captivity [1].Thus, the free ranging in fecundity rates and sometimes death [12].Overreindeer, in Northern England hardly harboured crowding, dampness and unsanitary conditions are Strongyle infections because of the sparseness of the predisposing factors for the proliferation of helminthic molluscan intermediate hosts in those areas, yet when infections [13].Such adverse conditions occur frequently they were relocated to zoos they showed high levels of under captivity than under free-living conditions [14, strongylosis [2].Most of the animals in Nigerian zoos 15].In as much as mixed infections of parasitic were once free living before they were subjected to infections have been reported in several domestic captivity.In order to ascertain the health status of wild animal species [16,17], and captive animals at Ibadan in South-Western single infections of mites [1] and mixed infections Nigeria, their bacterial and parasitic diseases were of nematodes [11,18] have also been reported in a extensively studied and reported [3][4][5][6][7].Similar studies variety of wild animals kept in captivity for long Statistical analysis of data: Data obtained were periods.This study was therefore, conducted at the either summarized as means ± standard deviation or Sanda Kyarimi Park in the semi-arid region of north-percentages and the difference between means were eastern, Nigeria in order to establish the helminth determined using the 't'-test at the 5% level of reservoir status of the captive wild ruminants.

Materials and Methods Results
The study area: The Sanda Kyarimi Park where this The helminth parasites of wild ruminants examined study was conducted is located in Maiduguri, the at Sanda Kyarimi Park Maiduguri are presented in capital and largest urban centre in Borno State, Table-1.A total of 36 captive wild ruminants, Nigeria.The state lies between the Sudan savannah representing nine (9) different species such as camel and Sahel vegetation zones characterised by a short (Camelus dromedarius), western kobs (Kobus kob), rainy season of 3 -4 months (June -September).The Senegal hartebeests (Damaliscus korrigum), rainy season precedes a prolonged dry season of more sitatungas (Tragelaphus speikei), cape elands than 8 months duration, when environmental (Tauratragus oryx), Grimm's duikers (Sylvicaprea conditions are not favourable for the development and grimmia), West African dwarf cattle, red fronted survival of pre-parasitic stages of parasitic helminths gazelles (Gazella rufifrons) and dama gazelles [10,11,19].
(Gazella dama) were examined.Worm burdens were expressed as mean egg counts per gram of faeces (epg) Collection of faecal samples: Faecal samples were among the different species of captive wild ruminants collected as they were freshly dropped from 36 captive examined.The various parasites encountered were wild ruminants.Each sample was labelled and expressed in percentages of which 3 (100%) of the accompanied with demographic data such as place of Senegal hartebeest examined tested positive for collection, age and sex of each animal.A total of 100 Strongyle eggs with a mean epg of 5, 350 + 51.7, while samples were collected during several visits to the park.
the helminth larvae recovered in this case was Examination of faecal samples: Faecal samples Trichostrongylus axei.Out of the three cape elands were examined for nematode ova by the simple (Tauratragus oryx) examined, all of them (100%) floatation technique using saturated sodium chloride tested positive for Strongyle egg with a mean epg of solution as floatation medium [20][21][22][23]   according to sex and their associated worm burden is reported to occur among captive wild ruminants in the presented in Table-3.same park [11].However, the present study recorded a 1(33.33%)out of the 3 Senegal hartebeests very high egg counts as compared to the previous (Damaliscus korrigum) examined during this study study.This study, which was conducted from June to was a male with 2 females.Both sexes tested positive September (rainy season), probably influenced the for Strongyle with a mean epg of 5,350 + 51.70, while high egg count.Most parasites tend to reach their the helminth larvae recovered were those of highest biotic potential during the rainy season [15].Trichostrongylus axei.Only 1(33.33%) of the cape Secondly, the larval infectivity and acquisition has eland (Tauratragus oryx) was a male, which tested been reported by several researchers to increase positive for Strongyle eggs.The other two were tremendously during the rainy season [1,6].females, which tested positive for Strongyle eggs with Furthermore, the general high egg counts encountered a mean epg of 960 + 21.90, and the helminth larvae among the wild ruminants as compared to those of an recovered were those of Haemonchus contortus.Out earlier study in the park [10,11] showed that the of the six Grimm's duiker (Sylvicaprea grimmia) deterioration of sanitary conditions in the park and examined during the study, 3(50%) were males while irregular anthelmintic medications over the years played 3(50%) were females.One (16.67%) out of the a vital role in the epidemiology of the infections.females tested positive for Strongyles while all the 3 The sitatunga (Tragelaphus spekei) and the males tested positive for Strongyle with a mean epg of Senegal hartebeest (Damaliscus korrigum) however, 500 + 10.00, with Haemonchus contortus larvae recorded the highest egg counts of 2,500 and 5,350 recovered.Out of the 6 sitatungas (Tragelaphus respectively due to Strongyle infection.The larvae speikei) examined 4 (66.7%) were males which tested recovered were those of Haemonchus contortus, and positive for both Strongyles and Strongyloides.Mean Trichostrongylus axei.Under normal circumstances, (epg) for Strongyle was 2,500 + 22.36 and 1,000 + such high egg count often resulted into overt disease or 14.14 for Strongyloides while Haemonchus contortus outbreaks among domestic animals [17].However, the and Trichostrongylus axei larvae were recovered.Two absence of overt clinical signs or death in this species out of the six sitatungas (Tragelaphus speikei) in the of wild ruminants in particular might be associated park were females and were negative for helminth with innate resistance to helminthosis due to their eggs.One (33.33%) out of the three West African reservoir status as wild animals [18].Despite these, it dwarf cattle examined during this study was a female has been reported that many cases of presumed which was positive for Strongyle eggs with a mean epg resistance to helminthosis in wildlife often break of 850 + 20.62 while the helminth larvae recovered down when subjected to the stress of captivity [1].were those of Haemonchus contortus.The remaining The camel (Camelus dromedarus) for the first two were males, which were positive for helminth ova.time harboured Trichuris trichuria, a parasite of humans The only camel (Camelus dromedarus) present in the and primates.This strange occurrence might be park during the study was a male in which Trichuris associated with 'spurious' infection or likely a new and Strongyle were encountered with a mean epg of host adaptation [17].Trichuris trichuria have been 550 + 23.45 and 800 + 28.28 due to Strongyles and reported among captive chimpanzee (Pan troglodytes) Trichuris specie respectively with H. contortus larvae in the same park [26].The occurrence of the same recovered.Out of the six dama, gazelles examined, parasites in several of the groups examined agrees two, (One male and one female) were positive for with previous reports [10,11] where one attendant was Strongyles, with a mean epg of 200 + 6.32 in both responsible for cleaning several pens, cages and enclosures cases, where Trichostrongylus axei was the helminth thereby acting as a vehicle of cross transmission larvae recovered.Strongyle was equally encountered between different animal groups.in two of the six red fronted gazelles (Gazella Conclusion rufifrons) present in the park, where 1(16.67%)male and 1(16.67%)female were positive for Strongyle The results of this study suggests that the captive with a mean epg of 700 + 11.83 with Trichostrongylus wild ruminants in the semi-arid region of northaxei larvae encountered.
eastern, Nigeria, are reservoirs of various helminth parasites of medical and veterinary importance.It was Discussion therefore, recommended that improved sanitary conditions, All the parasites recovered from the various in animal enclosures, balanced nutrition, environmental species of wild ruminants are common to domestic enrichment, regular and strategic anthelmintic medications animals in Nigeria [10].They have previously been may on one hand protect the spread of infection to

larval isolation and identification:
while, trematode 960 + 21.90, while helminth larvae recovered were ova were examined using sedimentation technique those of Haemonchus contortus.Similarly, out of the [24].The morphological identification of helminth six Grimm's duikers (Syvicapra grimmia) examined, 4 ova was done according to standard criteria [17, 21].Quantification examined, 1(33.33%)tested positive for Strongyle of helminth eggs was determined using modified McMaster technique with saturated sodium chloride eggs with a mean (epg) of 850 + 20.62, with solution as floatation medium [24] while larval Haemonchus contortus larvae recovered.Out of the isolation and identification to determine the species of six sitatungas (Tragelaphus speikei) examined, 4 helminths encountered was carried out using the (66.7%) tested positive for Strongyle and the helminth modified Baerman`s technique [17, 21].larvae recovered were those of Haemonchus contortus (66.7%) tested positive for Strongyle eggs with a mean (epg) of 500 + 10.0 with Haemonchus contortus larvae Estimation of egg count per gram of faeces / recovered.Out of the three West African dwarf cattle

Table - 1
. Helminth parasites of different species of captive wild ruminants examined at Sanda Kyarimi Park, Maiduguri, Nigeria In addition, 4 (66.7%)testedtestedpositive for both Strongyle and Trichuris specie positive for Strongyloides with a mean epg of 1,000 + with mean epg of 550 + 23.45 and 800 + 28.28 14.14 with the larvae of Strongyloides papillosus respectively, with Haemonchus contortus larvae recovered.Out of the 3 (100%) West African dwarf recovered.Two (53.33%) out of the six dama gazelles cattle examined, 1 (33.33%),adulttestedpositive for (Gazella dama) examined during this study tested Strongyle eggs with mean epg of 850 + 20.62 while the positive for Strongyle with a low (epg) of 22 + 6.32 larvae recovered were those of H. contortus.The only while helminth larvae recovered were those of adult camel (Camelus dromedarus) examined, 1 Trichostrongylus axei.(100%) was positive for both Strongyle and Trichuris A total of six red fronted gazelle (Gazella with an epg of 550 + 23.45 and 800 + 28.28 rufifrons) were examined in this study, where 2 respectively with Haemonchus contortus larvae (33.33%) tested positive for Strongyle egg with a recovered.Out of the six-dama gazelles examined, mean epg of 700 + 11.83 while helminth larvae five were adults and one young.One adult dama recovered were those of Trichostrongylus axei.gazelle and the only young tested positive for The age distribution of the helminth parasites of Strongyle eggs with a mean epg of 200 + 6.22 in both captive wild ruminants examined at the Sanda cases, with Trichostrongylus axei larvae recovered.Kyarimi Park, Maiduguri, Nigeria is presented in Six red fronted gazelles comprising of 5 adults and one Table-2.All three Senegal hartebeest (Damaliscus young were examined during this study.Strongyle with mean epg of 5, 350 + 51.70 tested positive for Strongyle with a mean epg + of 700 with Trichostrongylus axei larvae recovered.Three + 11.83 for both animals while the helminth larvae adult cape elands (Tauratragus oryx) were examined recovered were those of Trichostrongylus axei.andall 3(100%) were positive for Strongyle ova with aThe distribution of helminth parasites of captive mean epg of 960 + 21.90 while H. contortus larvae wild ruminants in Sanda Kyarimi Park, Maiduguri and Strongyloides papillosus with a mean epg of 2,500 were recovered.Out of the six sitatunga (Tragelaphus + 22.36 and 1,100 + 14.4 respectively while no speikei) examined, 4(66.7%) were young and infected parasite larvae were recovered from the two western with Strongyle with a mean epg of 2,500 + 22.38, kobs (Kobus kob) examined.whilehelminth larvae recovered were those of The only camel (Camelus dromedarus) examined Haemonchus contortus.

Table - 2
. Age distribution of helminth parasites of captive wild ruminants examined at Sanda Kyarimi Park, Maiduguri, Nigeria