Influence of season , age and breed on prevalence of haemoprotozoan diseases in cattle of Tamil Nadu , India

Materials and Methods Haemoprotozoan infections are very common in cattle and cause devastating losses to the livestock industry and pose a major threat to the dairy industry throughout the world [1]. Most of the haemoprotozoan parasites are transmitted by ticks and is of great economic importance in Asia and has always been a formidable barrier to the survival of exotic and cross bred cattle in India [2]. The hot and humid climate is very conducive for the development and survival of potential vectors such as ticks and flies and is a constant source of infection to susceptible animals [3]. Theileriosis, babesiosis and anaplasmosis are the three major tick borne haemoprotozoan diseases of crossbred cattle in tropical and sub-tropical regions of the world [4, 5, 6]. In India, the annual loss estimated due to tropical theileriosis alone is approximately US $ 800 million [7]. In the absence of adequate control measures, these haemoprotozoan diseases have serious economic impact on cattle production in terms of mortality, reduced milk yield and lowered draft power.


Materials and Methods
Haemoprotozoan infections are very common in cattle and cause devastating losses to the livestock industry and pose a major threat to the dairy industry throughout the world [1].Most of the haemoprotozoan parasites are transmitted by ticks and is of great economic importance in Asia and has always been a formidable barrier to the survival of exotic and cross bred cattle in India [2].The hot and humid climate is very conducive for the development and survival of potential vectors such as ticks and flies and is a constant source of infection to susceptible animals [3].Theileriosis, babesiosis and anaplasmosis are the three major tick borne haemoprotozoan diseases of crossbred cattle in tropical and sub-tropical regions of the world [4,5,6].In India, the annual loss estimated due to tropical theileriosis alone is approximately US $ 800 million [7].In the absence of adequate control measures, these haemoprotozoan diseases have serious economic impact on cattle production in terms of mortality, reduced milk yield and lowered draft power.
To undertake effective preventive measures, disease forecasting system must be in place, for which the pattern of disease occurrence in the past years at least 10 years are to be studied.Blood smears were received from the college hospital and veterinary dispensaries in and

Study area:
In India, haemoptozoan diseases have been reported from different geographical regions.The incidence of theileriosis was found to be 27.2% in cross-bred cattle with highest prevalence rate of 45.4% during rainy season in Dehradun district, Uttarakhand, India [8].The overall incidences of haemoprotozoan diseases , theileriosis (37%), babesiosis (10.41%), anaplasmosis (2.82%) was recorded in cross bred cattle in Anand district of Gujarat, India [9].In Northern Kerala, theileriosis and babesiosis have been reported as 16 % and 0.6%, respectively in crossbred cattle [10].An outbreak of theileriosis in cattle has been reported from Punjab with 4.86% mortality rate [11] Thin blood smears were fixed in methanol (5 minutes) and stained with Giemsa's stain (30 minutes) and were examined under oil immersion lens (100X magnification) for presence of blood parasites.The parasites were identified on the basis of characteristic morphology.Even the presence of a few piroplasms was considered to be positive.Parasitaemia in positive cases was graded as mild or severe by counting at least 10 randomly chosen oil immersion fields (Figure -2).Data were statistically analysed using one-way analysis of variance (ANOVA) (SPSS software version 17) at p < 0.05 regarded as statistically significant [12].All the values were expressed as mean and standard error of mean (SEM) and Microsoft excel was used for presentation of the results.
The analysis of data on the prevalence of haemo-protozoan parasites of cattle in Western part of Tamil Nadu for the period from 2003-2012 showed an overall prevalence of 16.64 %.Of which, theileriosis was 13 % followed by anaplasmosis 2.64 % and then babesiosis 1.0%.Among the haemoprotozoan diseases, the prevalence of tropical bovine theileriosis was found to be high, followed by anaplasmosis and babesiosis (Figure -1).It is important to note that, the prevalence of theileriosis has reached peak in the year 2004 and 2007 and also a similar trend was observed with anaplasmosis in the same period.Conversely, there was no fluctuation in the prevalence of babesiosis.
The prevalence of theileriosis was significantly (p<0.05)high during summer (14.4%), followed by moderate in monsoon (13.8%) and less in fair (11.5%) seasons (Table -1).However, there was no significant seasonal influence on the prevalence of babesiosis and anaplasmosis.
Screening of breed wise prevalence data revealed that there was a significantly (p<0.05)high prevalence of haemoprotozoan diseases in Holstein Friesian (HF) and Jersey cross breeds than indigenous breed (Table -2) and the occurrence of these haemoprotozoan diseases was found to be high among the age groups of 2-7 years in cross-bred animals and below 2 years in indigenous animals.
Our retrospective study revealed that 16.64 % of cattle were found infected with haemoprotozoan parasites and as single or mixed infections.Among the haemoprotozoan diseases, the prevalence of theileriosis was found to be high (13%), followed by anaplasmosis (2.64%) and babesiosis (1.0%).In India, theieriosis is a fatal parasitic disease and has been reported from various geographical regions of the country and recorded as 21.1 % in Tamil Nadu [13],  Mean with similar superscript in a column do not differ significantly (p 0.05).NS-Non significant.> 16% in Northern Kerala [10], 17.7% in Karnataka [14], 45.4% in Dehradun, Uttarakhand [8] and 4.86% in Punjab [11].These differences observed in the prevalence may be due to the different geographical locations of the study areas, time periods and various methods of sample analysis.It is interesting to note in the present study that an increased number of concurrent infections of theileriosis and anaplasmosis in the same period may be due to involvement of same species of ticks (probably spp.) in the transmission of both the haemoprotozoan diseases.Besides, spp. is the most common species of tick infesting cattle in Southern part of India [15,16] than spp.[17], which involves in the transmission of babesiosis.This could be the reason why low incidence of babesiosis was observed in this part of Tamil Nadu.

viz., Theileria annulata, Anaplasma marginale Babesia bigemina
Haemoprotozoan infection, particularly spp.infection reached peak during 2003 and then started declining (Figure -1).This could be due to regular usage of chemical control programme particularly the application of Deltamethrin (0.2% Butox) as a spray on animals and cattle shed which reduced the tick population under field conditions.The slow rise of infection during 2012 might be due to low rainfall and high temperature which favoured propa-gation of tick vector and in turn actively involved in the transmission of haemoprotozoan parasites (Figure -1).
An effort that was made to know the influence of seasonal variation on the prevalence of haemoprotozoan diseases, theileriosis was found to be significantly high during summer (14.4%), followed by moderate in monsoon (13.8%) and less in fair seasons (11.5%).The present investigation is in conformity with the report from Ranchi, Bihar [18], a high prevalence of theileriosis was observed during summer (17.64%), followed by rainy (7.32%) and less in winter (5%).On contrary, a few reports of higher prevalence of theileriosis were observed during monsoon season [9,19,20].The high prevalence of theileriosis observed in the present study may be due to high abundance of tick vector, because high temperature and humidity is ideal for survival and breeding of ticks [21,22].While studying the prevalence of babesiosis, it was recorded that highest prevalence during rainy season followed by summer and winter [23,24], but in the present study, there was no such seasonal influence on babesiosis and anaplamosis.A considerable seasonal variation with respect to the occurrence of the haemoprotozoan disease may be due to changes in macroclimate that is essential for breeding of ticks.Mean with similar superscript in a column do not differ significantly (p 0.05).>

Hyalomma Hyalomma
In the present study, screening of breed wise prevalence data revealed that cross-bred animals were mostly affected than indigenous animals.Breed susceptibility in this study are in line with observation made in crossbred cattle of Bangalore North [25].Further, it was observed in the present study that the occurrence of these haemoprotozoan diseases were found to be high among the age groups of 2-7 years in both the cross breeds and below 2 years in indigenous animals.This study supports the report witnessing animals over 3 years of age are highly affected by haemoprotozoan diseases in cross-bred animals [26].On contrary, the occurrence of babesiosis was found even in 15 days to 6 months old calf in this study.This made to suggest that inverse age resistance may fail to protect if there is any problem in maternal antibodies.Most of the cross-bred animals aged around 7 years were in the stage of 3 or 4 lactation as peak milk yielders.The weakening of immunity during high milk yielding stage in addition to genetic make up and seasonal stress in summer months could be reason for high susceptibility to this haemoprotozoan parasite.
The present study suggests that Western part of Tamil Nadu is highly endemic for theileriosis and occurrence of the disease was high during summer.Cross-bred animals, aged 2-7 years are highly susceptible to these haemoprotozoan diseases than indigenous animals.
The outcome of the present study would help to forecast disease outbreak not only in this region but also applicable to other parts of country.There is a need for further investigations using molecular techniques for the accurate identification of the carrier status of haemoprtozoan parasites.
RV, NR, GP, TJ, TA, KA, KS and PA-blood smear examination and identification of parasites.RV and GP-preparation of manuscript and analysis of data.All authors read and approved the manuscript.
The authors are grateful to the staff who had contributed their valuable data for this study during their tenure in this department and also we sincerely extend our gratitude to the Dean, Veterinary College and Research Institute, Namakkal for the facilities provided.The authors are thankful to Tamil Nadu Veterinary and Animal Sciences University, India for providing financial support throughout the study period.
The authors declare that they have no competing interests.

Figure- 1 :
Figure-1: Prevalence of haematoprotozoan diseasee in cattle recorded from January 2003 to December 2012 in and around Namakkal area.

Table - 1
: Seasonal pattern of blood protozoan in cattle recorded from January' 2003 to December' 2012 in Namakkal area.

Table - 2
: Age and breed wise prevalence of blood protozoan in cattle recorded from January' 2003 to December' 2012 in Namakkal area.