doi:10.5455/vetworld.2013.346-349 Sarcocystis infection in slaughtered cattle in Zango

Background: Sarcocystis infection is a parasitic zoonosis, which may cause acute and fatal clinical diseases in susceptible cattle. When raw or undercooked infected beef is consumed by man, it could result in intestinal sarcocystosis. 
 
Aim: This study aimed at determining the prevalence of Sarcocystis infection in slaughtered cattle in Zaria, Nigeria. 
 
Materials and Methods: A cross sectional study was conducted in which oesophagus and diaphragm samples were collected from 200 slaughtered cattle and analysed by pepsin-hydrochloric acid digestion and stained with Giemsa. Histological sections of tissues were prepared and stained with haematoxylin and eosin. 
 
Results: Eighty-five (42.5 %) were positive for Sarcocystis species. Sarcocysts ranged from 228.8 to 1215 μm in length and 46.93 to 114.40 μm in width. Sarcocysts were all microscopic in nature and 99.0 % had thin cyst wall ( 0.05). Seventy-five (88.2 %) and 56 (65.9 %) cattle had sarcocysts in the oesophagus and diaphragm respectively. There was a significant difference in the distribution of sarcocysts between the oesophagus and diaphragm (p < 0.05). 
 
Conclusion: This study has established in the study area the prevalence of Sarcocystis infection in cattle using tissue digestion 
method and histology. The identified species were of veterinary and public health importance.


Introduction
in pregnant cows naturally infected with Sarcocystis [5].Humans acquire the infection by eating infected Sarcocystosis is a parasitic zoonosis caused by raw or undercooked beef containing mature sarcocysts.species of Sarcocystis, an intracellular protozoan The current status of Sarcocystis infection in cattle in parasite in the Phylum Apicomplexa and Family Nigeria is unknown.Available information dates back Sarcocystidae.The infection is characterized by cyst to the work of Kudi in 1989 [6], hence this study.The formation in muscular tissues (muscular sarcocyctosis) objective of this study was to determine the prevalence in the intermediate host or colonisation of the lamina of Sarcocystis infection and to identify the species of propria of the intestines (intestinal sarcocystosis) in the Sarcocystis affecting slaughtered cattle in Zaria, definitive host [1].Sarcocystis has a requisite two-host Nigeria by using pepsin-hydrochloric acid digestion life cycle based on a prey-predator (intermediatemethod and histology.definitive) host relationship [2].Sarcocystis, once regarded as a non-pathogenic parasite, has been found

to be associated with disease conditions in both
Study area: The study area covered Zaria town of animals and man [3,4].There are three species of Kaduna state, Nigeria.Zaria is one of the major cities in Sarcocystis affecting cattle; Sarcocystis cruzi, S.
Kaduna state and as well a local government area, in hominis and S. hirsuta.Sarcocystis cruzi is the most North-west geo-political zone of Nigeria.Zaria lies in common [1] and pathogenic species affecting cattle the northern guinea savanna zone of Nigeria with leading to abortion, reduced milk yield, neurologic coordinates; 11.0667° N, 7.7000° E [7].The signs, loss of weight, hair loss and death (fatal cases), occupation of Zaria inhabitants is primarily agriculture depending on the species and number of sporocysts [7].Staples are guinea corn and millet; cash crops ingested [1].Abortion and placentitis has been reported include cotton, groundnut and tobacco.The major abattoir is located in Zango but there are also slaughter slabs in Sabon gari and Agoro.
Sample collection: Between January 2011 and July sediment stained with Giemsa and examined by optical 2011, 200 slaughtered cattle which included 65 males microscope at x 400 magnification for detecting and 135 females of 5 to 12 years old in Zango abattoir bradyzoites.An animal was said to be positive for of Zaria, Nigeria were examined for the presence of Sarcocystis infection, if either the oesophagus or sarcocysts and bradyzoites in muscular (oesophagus diaphragm contained sarcocysts/bradyzoites in the and diaphragm) tissues.The tissues were first digested tissue.examined grossly and 25 g of oesophagus and Positive samples fixed in formal saline were diaphragm were collected from each animal and submitted for histologic sectioning stained with transferred to the Parasitic Zoonoses laboratory of the haematoxylin and eosin (H&E).Photomicrographs of Faculty of Veterinary Medicine, Ahmadu Bello typical sarcocyst or bradyzoites were taken using a University Zaria, for microscopic examination.
digital microscope camera (Tucsen®).The length, Sarcocystis infection was classified into positive width and cyst wall thickness of the sarcocysts were and negative.The cattle were classified into 2 age taken using a calibrated micrometer eyepiece for the groups (5-8½ years and greater than 8½ years) based on differentiation of Sarcocystis species and compared visual inspection of the teeth, and into 2 breeds (White with reference values [1,10].

Fulani and Sokoto Gudali). White Fulani or Bunaji
Statistical analysis: Data collated at the end of the cattle is a white, black-eared and medium-horned study were analyzed using Statistical Package for breed, and is the most numerous and widespread of all Social Science (SPSS) version 17.0 (SPSS Inc.Nigerian cattle breeds.The Nigerian National Chicago, IL, USA) and subjected to statistical analysis Livestock Resource Survey (NNLRS) estimated that using descriptive statistics employing frequencies and they represent some 37% of the national herd [8].They percentages.Chi-square test of association was used to are found from Lagos to Sokoto, Katsina and Kano establish association between the infection status and States and spread across the North central geo-political variables such as age, sex and breed of the animal.zone.[8].There are two types of Gudali in Nigeria -the Mann-Whitney test was used to compare the Sokoto Gudali (or Bokolooji) and the Adamawa distribution of sarcocysts between oesophagus and Gudali.The Sokoto Gudali is a uniform cream, light diaphragm.P values less than 0.05 were considered grey or dun, the dewlap and skin folds are highly significant.developed and the horns almost absent.The NNLRS Results estimated that they represent some 32% of the national herd [8].
The overall prevalence rate of Sarcocystis infection in the 200 examined cattle, based on detection Digestion method: The method of Dubey et al (1989) of bradyzoites (Figure I) by tissue digestion was 42.5 [1] and its modification [9] were used for digestion of %.All sarcocysts observed were microscopic in nature.the muscles.Briefly, 25 g of each sample was minced, They ranged from 228.8 to 1215.5 µm in length and placed into a stomacher bag containing 5 ml of normal 46.93 to 114.40 µm in width.Of the positive samples, saline and homogenized using a stomacher.The 99.0 % were S. cruzi, having a thin cyst wall (< 1 µm) homogenate was suspended in 20 ml of digestion and 4.0 % S. hominis (Figure 2), having a thick cyst medium (1.3 g pf pepsin (BDH), 3.5 mL of 1% HCl and wall (3.61 to 7.22 µm).There was no significant 2.5 g NaCl in 500 mL of distilled water) and digested association (р > 0.05) between Sarcocystis infection for 1 hour at 37°C in a water bath.After digestion, the and age, sex and breed of cattle (Tables 1, 2 & 3).mixture was centrifuged at 1500 g for 5 minutes and the Seventy-five (88.2%) and 56 (65.9%) cattle had that were less than 500 µm in length.Some of the sarcocysts in the oesophagus and diaphragm sarcocysts were up to 1215.5 µm in length with thick respectively.There was a significant difference in the cyst wall and were microscopic in nature and identified distribution of sarcocysts between the oesophagus and as S. hominis.In histologic sections, S. hominis is diaphragm (p < 0.05) ( Table-4).
difficult to distinguish from S. hirsuta.However, sarcocysts of S. hominis is microscopic in nature

Discussion
whereas S. hirsuta is macroscopic at meat inspection Cattle become infected with Sarcocystis when [11].In this study, no macroscopic cyst was observed.oocysts/sporocysts of the parasite are ingested while The cyst walls of S. hominis and S. hirsuta can be grazing.The high prevalence (42.5 %) of Sarcocystis differentiated ultrastructurally [1].The finding of S. observed in cattle in this study is in contrast to 0 % hominis in cattle in this study poses a public health risk prevalence rate reported by Kudi [6].The increased because S. hominis is pathogenic in humans [1,12].detection rate of the parasite may be due to the Sarcocystis cruzi is the most prevalent and modification in the technique of the earlier work.The pathogenic species in cattle where it causes abortion, method was modified by mincing and homogenizing weight loss, neurologic sign, fever and death [1].The the tissues before digestion and staining of tissue result obtained in this study is similar to Savini et al., sediments with Giemsa stain.These procedures [13] who recorded a 52 % prevalence rate in Western probably enhanced detection of bradyzoites in tissue Australia.Da Silva [14] reported 100 % prevalence rate in Rio Grande do Sul State, Hamidinejat et al., [9] smears.In addition, the source of animals may reported 100 % prevalence rate in Ahvaz Khouzestan, contribute to the high prevalence recorded.Presently in south west of Iran while More et al., [15] reported Nigeria, most cattle are purchased from neighbouring 71.5% of S. cruzi cysts from beef cattle in Argentina.countries in contrast to the early 1970s and 1980s when The result of this study supports earlier reports about S. the country could rely on her own cattle population.
cruzi being the most prevalent species worldwide.Perhaps, the animals acquired the infection from these In the present study, age, sex and breed were not sources before transportation into the country.Fayer significantly associated with Sarcocystis infection in [2] reported that sarcocysts can persist for months or cattle which disagrees with the finding of Savini et al., years in the tissues of intermediate hosts.
[13] who reported that Sarcocystis infection in cattle in Also, cattle farm owners/nomadic cattle rearers in Western Australia was influenced by age, sex, Nigeria use dogs as security tools (dog shepherds) to environmental and management factors.In that study, protect their animals from danger.For nomads, they cattle included in the study were less than 1½ years to graze their cattle over various pastures moving from greater than 4 years of age.Sarcocystis infection one location to another.The presence of dogs and other significantly dropped in cattle greater than 4 years of definitive hosts including non-human primates in the age.In the present study, the age range of cattle grazing pastures of the animals ensures shedding of the sampled was from 5 to 12 years (older cattle).This infective oocysts into the environment, which in turn factor could have masked the effect of age on infect the animals.Moreso, Sporocysts or oocysts of Sarcocystis infection, as calves were not sampled.Sarcocystis remain viable for many months in the However, a lower prevalence was observed in the older environment, and they may be further spread or cattle, when compared to those between 5 to 8½ years, protected by invertebrates [1].
although the difference was not significant.Host The Sarcocystis species observed based on the immune response to the infection may be responsible morphometric features of the sarcocysts were S. cruzi for the fall in prevalence in the older cattle.and S. hominis.Sarcocystis cruzi was identified based Sex was also not a determinant of the infection in on its microscopic nature, thin cyst wall and sarcocysts

Table - 1
. Age specific prevalence of Sarcocystis species in tissues (oesophagus and diaphragm) of slaughtered cattle in Zango abbatoir, Zaria, Nigeria