Epidemiology- Diagnosis and Control of Haemoprotozoan Parasitic Diseases of Animals
Ticks are recognized as important vectors of blood protozoan diseases in livestock. Out of 867 tick species recognized globally, 10 percent of them act as the vectors of pathogens of domesticated animals and human beings (Jongejan and Uilenberg, 2004). Climatic factors, particularly temperature, are considered to be important determinant for tick propagation. Cattle ticks are responsible for severe economic losses in both dairy and beef cattle enterprises in the tropics (Jonsson, 2006). It is obligatory blood-sucking arachnid arthropods infecting mammals, birds, reptiles and amphibians. They are vectors of diseases, causing anemia, dermatitis, paralysis, otocariasis as well as loss of production Three families of ticks are established, but two of them Ixodidae (hard ticks) and Argasidae (soft ticks) are well known and of veterinary importance (IMR, 1995). In Nepal, five genera were identified viz. Boophilus, Hyalomma, Rhipicephalus, Haemaphysalis and Ixodes. Among them Boophilus microplus was the most abundant in all agro climatic zones and in most of the farm animals namely bovine, buffalo, goat, pig and rabbit (Shrestha et al., 2005). Haemoparasitic diseases have a global distribution, stretching from the polar circle to the equator. This is due to the fact that their vectors, ticks and blood sucking flies have a global distribution. Tick borne haemoparasistes includes all tick-borne organisms which are visible with light microscope and which occur in the circulating blood as part of their life cycle (Uilenberg, 1995). Among the parasitological problems, the damage caused by tick borne diseases is considered very high (Ghosh et al., 2007). The most important haemoparasites are Babesia, Theileria, Anaplasma and Trypanosoma. These haemoparasites are transmitted through ticks (Zahid et al., 2005). Haemoparasites are of great economic loss due to the morbidity and mortality. It is a major threat to food security especially among the livestock dependent communities within the sub Saharan Africa (Kasozi et al., 2014). Haemoparsites have generally been shown to cause destruction of red blood cells resulting in anemia, jaundice, anorexia, weight loss and infertility. The occurrence and important of haemoparasite is a reflection of complex interaction involving the causative organisms, vector, the vertebrate hosts and the environment (Akande et al., 2010). Arthropod transmitted haemoparasites diseases are economically important vector-borne diseases of tropical and subtropical parts of the world including Ethiopia. Tick borne haemoparasitic diseases of ruminants are caused by the Babesia, Theileria, Anaplasma and Trypanosoma species and all the intracellular parasites species (Sitotaw et al., 2014). Anaplasmosis is a vector borne blood diseases in cattle caused by the member of genus Anaplasma. In cattle, this disease is caused by A. marginale and A. centrale; later less pathogenic than former (Sajid et al., 2014) where as in sheep and goats A. ovis is the important causative agent (Radwan et al., 2013). Anaplsamosis is not contagious; numerous species of tick vectors (Boophilus, Dermacenter, Rhipicephalus, Ixodes and Hyamomma) can transmit Anaplasma species (Rymaszewska and Grenda, 2008). Not all of these are likely significant vectors in field and it has been shown that strains of A. marginale also co-evolve with particular tick strain. After feeding on an infected animal, transmission may occur. Transovarian transmission may occur although even in a single host Boophilus species (Kahn, 2005). Anaplasmosis may also be spread mechanically by infected hypodermic needle, castrating, spaying and dehorning instruments, blood trasnsfusion and embryo transplant. Additionally intra uterine infections also occur in cattle but much less frequency in field cases than in experimental one. Anaplasma can transmit by bitting flies to the family Tabanidae (Radostits et al., 2007). It is found in endemic in all six populated continents of the world; mostly in the tropics and subtropics because of the broad range of vectors and difficulties of efficient vector control (Sajid et al., 2014). Bos taurus breeds are more likely to develop acute Anaplasmosis than crossed Zebu, but Bos indicus are not commonly affected because of their resistance to heavy tick resistance (Kocan et al., 2003). Anaplasmosis is characterized by fever, weight loss, decreased milk production, pale mucous membranes, severe anemia, jaundice, hyper- excitability abortion and mortality without hemoglobinemia and haemoglobinuria during acute phase of the infection (Atif et al., 2013). Tetracycline compounds are effective in treatment if given early in the course of the disease and especially before the parasitaemia has reached its peaks (Lefevre et al., 2010). Babesiosis is also called piroplasmosis, cattle fever, red water fever or Texas fever. The causative agents of babesiosis are specific for particular species of animals. In cattle: B. bovis, B. bigemina, B. divergens and B. major (Radostits et al., 2007). B. bovis and B. motasi are known to be pathogenic agents in sheep and goats (Fakhar et al., 2012). Babesia species is transmitted by hard ticks in which Babesia passes transovarially via the egg from the one tick generation to the next (Ijaz et al., 2013; Urquhart et al., 1996). Babesiosis occurs throughout the world (Fakhar et al., 2012). However the distribution of the causative protozoa is governed by the geographical and seasonal distribution of the insect vectors. The vector of Babesia, Boophilus microplus is wide spread in tropics and sub tropics (Chaudhary et al., 2010). Bovine babesiosis associated with B. bigemina and B. bovis are an important disease of tropical and sub-tropical regions of the world. Both species are transmitted by the Boophilus ticks, but only tick larvae transmit B. bovis, whereas nymphs and adults transmit B. bigemina and B. divergens. Bovine babesiosis transmitted by Ixodes ricinus is widespread. Small ruminant babesiosis is caused by the B. ovis (Esmaeilnejad et al., 2015). Bos indicus breeds of cattle are more resistance to babesiosis than Bos taurus (Kamani et al., 2014). Babesia produces acute disease by two principle mechanism; hemolysis and circulatory disturbance (Carlton and McGavin, 1995). Theileriosis is a group of tick borne disease caused by Theileria species. It is intracellular protozoan parasites infecting leukocytes and erythrocytes of wild and domestic large and small ruminents. In cattle, T. parva, T. mutans, T. velifera, T. lestoquardi, T. ovis and T. separate (Mandal, 2012). T. annulata and T. parva are considered to be the pathogenic species of Theileria affecting cattle (Kohli et al., 2014). T. lestoquardi is the most virulent species in sheep and goats (Kahn, 2005). Theileria species that infect cattle and ruminants are transmitted by ixodid ticks of the genera Rhipicephalus, Amblyomma, Hyalomma and Haemaphysali (ILO, 2004). Theileria sporozoites are transmitted to animals in the saliva of the feeding tick (Mandal, 2012). T. parva lawrencei responsible for corridor disease transmitted from buffalo to cattle and T. parva bovis, the causing agent of Zimbabwe theileriosis, a more benign from also known as “ January disease” (Nambota et al., 1994). Theileriosis occurs when there is much tick activity, mainly during summer but a single tick can cause fatal infection (Hassan, 2010). Trypanosomosis is an important disease of both humans and animals commonly found in most parts of Africa and South America (Swallow, 2000). The tsetse fly (Glossina) is responsible for biological transmission while haematophagus arthropod vectors of the family Tabanidae, Stomoxynae and Hippoboscidae are responsible for its mechanical transmission (Soulsby, 2012). Transplacental transmission has also been recorded in cattle (Ogwu et al., 1992). Trypanosoma congolense, T. vivax and T. brucei have been reported to cause nagana in cattle while T. evansi caused surra in camels (Mbaya et al., 2010). In humans, Trypanosoma brucei gambiense and Trypanosoma brucei rhodeseinse are responsible for human sleeping sickness in West and East Africa respectively, while T. cruzi, transmitted by triatomid bugs (Triatoma magista) is responsible for transmitting chagas diseases to humans in South America (Solano et al., 2000). The T. brucei group of trypanosomes (T. brucei, T. b. gambiense, T. b. rhodesianse and T. evansi) mostly invade tissues (humoral) whereas, T. congolense and to a lesser extent T. vivax and T. cruzi predominantly restrict themselves to the blood circulation (Igbokwe, 1994; Mbaya et al., 2011).
Epidemiology- Diagnosis and Control of Haemoprotozoan Parasitic Diseases of Animals
Epidemiology, Diagnosis and Control of Haemoprotozoan Parasitic Diseases of Animals
