Tick species of India, hosts and distribution

India is predominantly an agricultural country with about 70% of its population dependent on income from agriculture. Farmers are keeping animals for milk, meat, wool, and hide production and also for various farm operations. India accounts for a significant share of the world’s livestock resources with nearly 57% of world’s buffaloes, 16.5% cattle, 16.3% goats, and 5.7% sheep (FAO 2004). Livestock is an important source of animal protein for farm families and also used for draught power in agriculture and transport, and their dung is used to increase soil fertility. In India, the damage caused by ticks and tick borne diseases (TTBDs) to livestock is considered very high (Ghosh et al. 2006). A recent estimate of US$ 498.7 million per annum has been calculated as the cost of TTBDs in India (Minjauw and McLeod 2003).

Tick specimen were collected from different animal sheds of large organized farms and village-level small farms. Ticks species reported from different states in India (Fig. 1) are listed in Table 1. It was observed that a number of tick species are reported from same host species (Table 2). Disease transmission potential have been reported for Boophilus (bovine babesiosis and anaplasmosis), Haemaphysalis (theileriosis and babesiosis in sheep and goats), Hyalomma (bovine tropical theileriosis, equine babesiosis), Rhipicephalus (canine babesiosis, ehrlichiosis and equine babesiosis), and Argas (aegyptianellosis, spirochaetosis in birds).

Fig. 1
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Map of India and its states

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Table 1 Distribution of ticks in India
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Table 2 Distribution of tick species in different hosts
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Tick prevalence in Pakistan

In Pakistan, ectoparasites are one of the major health hazards in livestock leading to colossal economic losses such as lowered productivity and mortality. Production of the animals is affected because of the parasitic nature of the ticks and because of the fact that they transmit important protozoan diseases like babesiosis and theileriosis (Gray and Potgieter 1982; Riek 1982). The distribution of ticks in two provinces of Pakistan (Fig. 2) is summarized in Table 3.

Fig. 2
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Map of Pakistan and its provinces

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Table 3 Distribution of ticks in two provinces of Pakistan
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A number of studies have been conducted in different geographical areas of Pakistan to investigate the prevalence of ticks on livestock. Eighteen thousand animals comprised of 4,500 each, cattle, buffaloes, sheep, and goats were examined for tick infestation from three districts of Faisalabad division. The rate of tick prevalence was highest (28.2%) in cattle followed by sheep (18.8%), buffaloes (14.7%), and goats (12.3%). Fluctuations in the rate of tick infestations also have been reported in different regions of the same geographics. Kosar (1965) reported an incidence of 3.16, 3.25, 4.21, and 2.63% in cattle, buffaloes, sheep, and goats, respectively. Likewise, 15% cattle, 26% buffaloes, 29% sheep, and 30% goats have been found tick infested in Sindh, Pakistan (Hussain 1980).

The variation in tick prevalence in different areas is attributed to a variety of factors like geo-climatic conditions, association and life style of different species of animals, awareness/education of the farmers, and farm management practices. It is evident from the results that significant differences exist in the tick prevalence between different species of animals. During the study, it was observed that herds of sheep and goats were grazed together; cattle grazed separately, and buffaloes were noted usually to be stall fed with few exceptions. This might have resulted in less exposure of routinely stall-fed animals (buffaloes and goats) to the tick infestation from widespread-infested pastures. However, the possibilities of genetic differences leading to varied resistance against tick cannot be ruled out, which may be explored by further studies on the genetic make-up of these animals.

Tick species identified in Pakistan

Rhipicephalus sanguineus, Boophilus microplus, B. annulatus, Hyalomma anatolicum anatolicum, H. isaacii, H. aegyptium, and Dermacentor marginatus were identified from cattle, buffaloes, sheep, and goats (Kaiser and Hoogstraal 1964). Although infestation with a single species of tick were recorded, most of the animals examined during the study had mixed infestation with different tick species. A similar trend of tick infestation has been observed by different workers (Drummond 1967; Iqbal 1971). However, variation in the rates of prevalence between single and mixed infestation exist, which can be attributed to the exposure of the animals and/ or innate resistance to some species of ticks (Daynes and Gutierrez 1980).

Besides the abovementioned species, the following ticks have been recorded in Pakistan: Boophilus sharifi sp. nov., Haemaphysalis cornupunctata, Haemaphysalis montgomeryi, Hyalomma anatolicum excavatum, H. detritum, H. kumari, H. hussaini, H. turanicum, H. dromedarii, Rhipicephalus appendiculatus, R. haemophysaloides, Dermacentor raskemensis, Argas reflexus, Argas vespertillionsis, Argas persicus, and Argas abdussalami. As regard to diseases transmission, Hyalomma species have been reported to transmit theileriosis (Khalid et al. 1991; Khan 1991) while Boophilus species transmit babesiosis (Khan 1991).

Ticks in Bangladesh

Ticks species reported from different divisions in Bangladesh (Fig. 3) are listed in Table 4.

Fig. 3
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Map of Bangladesh and its divisions

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Table 4 Distribution of ticks in Bangladesh
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More than a dozen tick species have so far been recorded from Bangladesh infesting cattle, goat, sheep, dog, wild mammals, birds, and lizards (Rahman and Mondal 1985). The cattle tick, B. microplus is predominant, followed by Haemaphysalis bispinosa, Hyalomma truncatum and H. anatolicum. The other common species are Amblyomma gervaisi, H. canestrini, Haemaphysalis kinneari, R. sanguineus, Rhipicephalus evertsi evertsi, and Amblyomma variegatum among the hard ticks, and A. persicus, the fowl tick, among the soft ticks infesting poultry. B. microplus has occasionally been found to infest human beings. An ecological investigation of tick and tick-borne blood protozoa in animals of Madhupur Forest Area, Tangail, Bangladesh, was conducted during July 1999 to June 2000. Animals like cattle, goats, dogs, pigs, jackals, cats, civets, mongoose, and horses and animal attendants have been examined for tick infestation. B. microplus infestation in 28.3% cattle, 6.3% goats, and 100% animal attendants and H. bispinosa in 7.6% cattle, 55.4% goats, and 13.2% pigs have been found. R. sanguineus in 59.4% dogs and 16.7% jackals and H. kinneari in 66.7% jackals have also been found. None of the cat, horses, mongoose, and civets was found to be infested with ticks.

In a very recent study, Islam et al. (2006) investigated the distribution, host preference, and population density of ixodid ticks in Bangladesh and found that in three distinct topographic zones, viz. flood plains, hills, and steppe ‘Barind,’ five species of ixodid ticks were recorded namely, B. microplus (56.3%), H. bispinosa (11.3%), R. sanguineus (14.7%), H. anatolicum anatolicum (15.0%), and Amblyomma testudinarium (2.8%).

In addition, they found that B. microplus predominantly infested cattle (42.4%), followed by goats (25.5%), buffaloes (12.5%), and pigs (8.2%). H. bispinosa mostly parasitized goats (31.5%), cattle (12.0%), and buffaloes (10.8%), whereas R. sanguineus principally infested dogs (27.4%) and to a lesser degree cattle (10.8%) and goats (6.8%). While H. anatolicum anatolicum was restricted to cattle (19.2%), A. testudinarium infested both cattle (4.4%) and pigs (2.3%).

The population density of these ticks was significantly influenced by the changing of seasons. B. microplus, H. bispinosa, and R. sanguineus were by far the most widely distributed species; the distribution of H. anatolicum anatolicum was restricted to the steppe ‘Barind Tract’ and A. testudinarium was found in the hilly regions only (Mondal et al. 1995).

The recorded important ticks, which infest ruminants, are B. microplus, H. bispinosa, R. sanguineus, and H. anatolicum. Almost all the ruminants are infested throughout the year with minimum load of these ticks. The load is occasionally very high (several hundreds) in young ruminants and alarmingly high in exotic or crossbred animals. All the ticks have a wider distribution, but H. anatolicum is only confined to the northwestern dry regions (Rajshahi, Rangpur, and Dinajpur districts) of the country.

An overall of 12,778 ticks has been collected from different animals of many districts of Bangladesh, of which 5,760 examined for species identification. The identified ticks are: B. microplus, H. bispinosa, H. kinneari, H. canestrini, A. gervaisi, A. variegatum, R. sanguineus, R. evertsi evertsi, H. anatolicum anatolicum, and H. truncatum.

Boophilus microplus (Canestrini)

More than 80% of cattle examined has been found infested with almost all the stages of tick. The ratio for different stages are male 17.5:female 54:nymphs 22.6:larvae 5.5. The load of tick infestation varies from 3 to 184. Goats have been found infested with a few adults (maximum of seven ticks from a goat) of B. microplus. Dog and pigs are also found to harbor adult B. microplus. On one occasion, a partly engorged female of B. microplus has been recorded from the inner side of the ear of a 9-month-old child from Muktagacha, Mymensingh, and two engorged females of B. microplus from the head of a Cobra (Naja naja) from Mymensingh, Bangladesh. Calves are usually more infested than adults.

Haemaphysalis bispinosa (Neumann)

About 40% cattle has been found positive for H. bispinosa infestation. The ticks are mostly adults and in few cases engorged nymphs. The load of tick infestation varies from 1 to 25. In goats, the percentage of infestation of this type of tick is about 74%. The tick load varies from 3 to 43. The ratio for different stages of tick is male 18.7:female 35.0:nymph 25.3:larvae 21.0. Only unengorged adult H. bispinosa are found in cats, dogs, and pigs attached to the ears. Other preferred hosts for all stages of this tick are monkey (Macaca sp.), civet (Viverra zibathi), and foxes (Vulpes bengalensis) found in forest areas of Madhupur in Mymensingh districts, Bangladesh.

Haemaphysalis kinneari (Warburton)

Mixed infection with H. kinneari and H. bispinosa are found in foxes. Immature ticks like to inhabit the head of the civet found in the hilly area in Mymensingh, Bangladesh.

Haemaphysalis canestrini (Supino)

Both male and female ticks have been collected from the body of foxes from the hilly area of Mymensingh, Bangladesh.

Amblyomma gervaisi (Lucas)

This species is found in varanid lizards (Baranus bengalensis), in Mymensingh and Sylhet district in Bangladeh. Both adults and nymphs prefer to attach to a grove around the anus of the lizards.

Amblyomma variegatum (Fabricius)

It has been recorded from the body of a dog in the Savar Dairy Farm, Dhaka, Bangladesh.

Rhipicephalus sanguineus (Latreille)

Adult ticks of the species are recorded from dogs and cats from Dhaka, Mymensingh, Comilla, and Sylhet. On one occasion, two males of R. sanguineus were found attached to the ear of a cow in Mymensingh, Bangladesh.

Rhipicephalus evertsi evertsi (Neumann)

In one occasion, a few adults of R. evertsi evertsi were found on a dog at the Savar Dairy Farm, Dhaka, Bangladesh.

Hyalomma anatolicum anatolicum (Koch)

Only adults are found on cattle in the Rajshahi and Dinajpur areas of Bangladesh.

Hyalomma truncatum (Koch)

This tick has been recorded from a Friesian cow of Savar Dairy Farm, Dhaka, Bangladesh.

Seasonal incidence

Animals are found to be infested with ticks throughout the year. Seasonal occurance of B. microplus varies with the tick load; it is found that in the month of May, the tick load is increased because of the availability of favorable environmental conditions in April thus favoring embryonic development and increased larval activity for infestation of cattle. Heavy rainfall in June causes sharp decreases in tick load because of physical injury or the washing away of larvae. Rainfall in August creates suitable conditions for larval activity leading to a rise of load in September. Other possible factors for this bimodal peak could be loss of body vigor of cattle because of shortage of food and stress conditions in the winter and rainy season.

The risk period for H. bispinosa is in the month of June as the infestation in cattle and goats are found to be positively associated with rainfall and evaporation rates and negatively associated with ambient temperature.

Examination of cattle for ecological investigation of H. anatolicum anatolicum tick at Rajshahi district showed higher rates of infestation during summer followed by monsoon and lowest during winter. The tick infestation was found to be influenced by temperature, rainfall, and relative humidity. The prevalence of H. anatolicum anatolicum in greater Rajshahi district, Bangladesh, may be due to the dry and steppe climatic condition and vegetation.

Diseases transmission

Ticks are responsible for the transmission of a number of pathogens. Blood sample examination revealed Babesia bigemina infection in 6.2%, Theileria annulata in 0.4%, Theileria mutans in 10.8%, and Anaplasma sp. in 0.8% cattle, Theileria ovis in 14.6% goats, and Babesia canis in 10.2% dogs.

It has been found that B. microplus is the vector of both B. bigemina and Babesia bovis; transmission is always trans-ovarian. Only on a few occasions, it has been reported from buffaloes. B. bovis is also sporadically reported from cattle.

H. bispinosa and R. sanguineus are implicated as vectors of Babesia motasi and B. ovis, which have been sporadically recorded in sheep and goats in Bangladesh. R. sanguineus is involved in the transmission of Babesia equi, which has been recorded in horses and donkeys.

Conclusion

Ticks are widely distributed in Bangladesh, India, and Pakistan. They are transmitters of numerous etiologic agents that pose serious threats to both public health and livestock industry in the region. The lack of accurate data on the epidemiology of TTBDs in the region makes it difficult to determine their impact, and more research work is necessary to identify the economic losses because of TTBDs.