Study was conducted to determine the prevalence of naturally occurring enteric parasites in calves of Jabalpur region and the pathological effects produced by them contributing to calf mortality. Examination of faeces collected from diarrhoeic as well as non diarrhoeic calves revealed the presence of Eimeria, Strongyles, Toxocara, Strongyloides, Trichuris, Moniezia, Amphistome and Fasciola spp. eggs. The overall prevalence of gastrointestinal parasitic infection was determined to be 84.52 per cent (142/168). A significant association was found between presence of entero parasite infection and diarrhoea in calves. Coagulative necrosis in liver, gland destruction in abomasums and desquamated intestinal epithelium were the predominant microscopic changes noticed in present study.
Gastrointestinal (GIT) parasites in calves cause reduced growth rate, delayed age of maturity and death particularly in neonatal calves thereby affecting the development of livestock industry. Helminths such as ascarids, gastrointestinal (GI) strongyles as well as coccidia are responsible for chronic diarrhoea with high morbidity and mortality rate (Jyoti et al., 2012). Bovine coccidiosis occurs in all parts of the world and serious outbreaks may occur in dairy herds where young stocks are kept in large numbers (Kaur and Devi, 2014). Cryptosporidium parvum has been associated with neonatal calf diarrhoea and 1 to 3 week-old calves are most susceptible. Giardia intestinalis infects dairy calves as young as 4 days of age but the main prevalence occurs at 5-10 weeks of age with the highest cysts excretion in faeces at 1-6 weeks of age (Singh et al., 2006; Squire et al., 2013). As part of good husbandry practices it becomes essential to control GIT parasitism in calves and for this knowledge on prevalence of these parasites is mandatory. Study was conducted to determine the prevalence of naturally occurring enteric parasites in calves of Jabalpur region and the pathological effects produced by them contributing to calf mortality.
Material and Methods
Cattle and buffalo calves below six months, of either sex, belonging to organised and unorganised farms of Jabalpur were included in the study. To know the prevalence of gastro intestinal parasites total 128 faecal samples were collected from both diarrhoeic as well as non diarrhoeic calves during the study period of 8 months. Of these 108 were cattle calves and 20 were buffalo calves. Apart from this the intestinal contents from 40 dead calves with gross post mortem lesions of enteritis, were collected and examined for presence of parasites. Thus, total 168 samples (128+40) were examined for parasitic infections by the direct smear, flotation and sedimentation techniques. The 128 faecal samples and 40 intestinal contents collected from dead calves were also processed for E.P.G./O.P.G count of different entero-parasites by Mc Master Technique (Soulsby, 1982). Prevalence of Cryptosporidium spp. in calves was determined by staining the faecal/intestinal smears by modified Ziehl Neelsen method. The liver, abomasums and intestinal tissue from 40 post mortem cases with gross lesions of enteritis and heavy parasitic load in intestinal content were also collected and processed for histo-pathological examination using standard techniques.
Results and Discussions
From the total 128 faecal samples collected from live calves 110 were found positive for parasitic infections. In the 40 cases of intestinal samples collected from dead calves, 32 were positive for parasitic infections. Thus, the prevalence of gastrointestinal parasitic infection was determined to be 84.52 per cent (142/168) in calves of Jabalpur region. Examination of faeces collected from total 128 diarrhoeic as well as non diarrhoeic live calves revealed the presence of Eimeria, Strongyles, Toxocara, Strongyloides, Trichuris, Moniezia, Amphistome and Fasciola spp. eggs (Table 1; Fig. 1).
Table 1: Species wise prevalence of entero-parasites in calves
|Enteroparasite||Calves with Diarrhoea||Healthy Calves||Total Samples|
|N (61)||%||N (67)||%||N(128)||%|
|Fig. 1a: Fasciola eggs||Fig. 1b: Mixed parasitic eggs/oocysts|
Amongst the ante-mortem faecal samples 46/61 (75.40 %) samples collected from calves with diarrhoea, and 64/67 (95.52 %) samples collected from non diarrhoeic calves where found positive for parasites. Chi-Square test was used to determine association between diarrhoea and entero-parasite in faeces of calves. A significant association was found between presence of entero-parasite infection and diarrhoea in calves (Table 2).
Table 2: Association between entero-parasite infection and diarrhoea in calves
|Diarrhoeic||Non-Diarrhoeic||Total Sample||Prevalence (%)|
c2 = 10.687S, Significant at p< 0.05 ; Relative risk analysis : 0.501
However, an interesting finding was the presence of parasites in significant number (64/67) of non diarrhoeic faecal samples also. This indicates that a subclinical parasitic infection of parasites may be prevalent plausibly leading to reduced weight gain. Squire et al. (2013) observed that although diarrhoea is a main symptom of gastrointestinal parasite infection, there was no significant association between diarrhoea and parasite prevalence in their study. This implies that several of the infected animals may remain asymptomatic. The workers opined that this could also be as a result of the generally low parasite egg output (E.P.G. / O.P.G.) by most of the animals.
The intestinal content from 40 post mortem cases with gross lesions of enteritis were also examined for the presence of parasite stages. Amongst the 40 post mortem cases with enteritis (Fig. 2), prevalence of entero-parasites in cattle calf was determined to be 77.27 per cent (17 out of 22 cattle calves) as compared with 83.33 per cent (15 out of 18) in buffalo calves. Relative risk analysis was calculated as 0.927. The non significant value of Chi-square test indicates that there is no significant difference in the prevalence of entero-parasites between cattle and buffalo calf.
|Fig. 2: Congested haemorrhagic intestine of 3 month cattle calf with mixed parasitic infection|
Variable incidence (67-75%) of parasitic infection has been reported by different workers in buffalo and cattle calves from different areas (Samad et al., 2004; Bilal et al., 2009). Jyoti et al. (2012) determined prevalence of GI parasitic infections as 73.58 per cent in calves of Punjab. Most of these earlier workers attributed the high prevalence of gastrointestinal parasitism to lack of hygienic conditions prevailing in the farms. In the present study the prevalence of parasites in calves was found to be very high which again could be an indication to poor management prevailing in most of the dairy farms of the region. In the present study Mc Master Count revealed maximum samples having less than 1000 E.P.G. / O.P.G. (Table 3). Samad et al. (2004) have stated that an E.P.G. >200/g and O.P.G. >5000/g of faeces should be considered significant for clinical infections.
Table 3: Mc Master Count of parasitic eggs/oocyst
|Enteroparasite||Eggs/Oocyst per gram of Faecal Sample|
Maximal prevalence of parasites was recorded in the month of August with 91.42 per cent samples. Earlier workers have also observed a high parasitic prevalence in bovines during the rainy season as warm and humid weather prevails the growth and development of larva (Saha et al., 2013; Kaur and Devi, 2014). Cattle are commonly infected by Cryptosporidium parvum, C. bovis, C. ryanae, C. andersoni. and C. parvum is considered a primary cause of calf diarrhoea and is potential zoonoses. Ziehl-Neelsen staining was done of 168 faecal and intestinal samples collected from diarrhoeic, non-diarrhoeic and dead calves. The technique could detect 38.69 per cent positive cases of Cryptosporidium spp. in faecal and intestinal samples (Table 4; Fig. 3). Counting of oocysts revealed more than 10 oocyst/smear in 05 diarrhoeic and 2 non diarrhoeic animals.
Table 4: Cryptosporidium oocyst in faecal samples
|Diarrhoeic (61)||Non diarrhoeic (67)||Post-mortem (40)||Total (168)|
|Fig. 3: Cryptosporidium oocyst in intestinal content of 1.5 month old buffalo calf|
Our results are in accordance with Agrawal et al. (2014) who screened 219 faecal samples from bovine calves in Jabalpur region, and found 34.70 % positive for Cryptosporidium spp. oocyst.
Gastrointestinal parasitism may be associated with an array of lesions depending upon the type of parasite (Fig. 4). In present study from the post mortem cases, maximal (n=20) were of mixed parasitic infections. Liver, abomasums and intestine of these animals had congestion, haemorrhages and areas of necrosis (Fig. 5). Coagulative necrosis was the predominant microscopic change noticed in liver, abomasums had gland destruction and different parts of the intestine showed mainly desquamation of epithelium (Fig. 6). Intestinal villi atrophy (Fig. 7) and stunting lead to malabsorption and reduced weight gain. However, the alterations in the architecture of the intestinal mucosa were not unique to any infection. It is suggested that since the animals could be harboring bacterial or viral infections also along with the parasites, the pathological lesions were probably the result of two or more concurrent infections.
|Fig. 4: Microscopic section of buffalo calf intestine having coccidia in various developmental stages; Oocyst (small arrow), macrogamonts (long arrow).||Fig. 5: Visceral organs of 3 month old cross breed calf with mixed parasitic infection. Congested intestine and areas of necrosis on liver.|
|Fig. 6: Microscopic section of cattle calf intestine with Eimeria infection having desquamation and degenerated epithelial cells in lumen.||Fig. 7: Microscopic section of intestine of cattle calf with mixed parasitic infection having clubbed atrophic villi. H & E X400)|
In conclusion, gastrointestinal parasites are highly prevalent in cattle from the study area. There was a wide variety of parasites with most animals having multiple parasitic infections. The pathologists need to have a high index of suspicion to come to a diagnosis. To make a firm diagnosis of intestinal parasitism it is necessary to demonstrate substantial population of parasites by count in the intestinal content and ideally to observe villus atrophy in tissue sections of infected intestine. It is also recommended that the economic impact of these parasites on livestock production in Jabalpur should be established. In addition, it is necessary to assess the current control strategies to improve production.