Clinicopathological Study Of Theileriosis In Naturally Infected Sheep
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Publisher: 2013 Dissertation note: Theleiriosis in sheep is an important infectious disease of small ruminants characterized by General weakness, weight loss, anorexia, elevated body temperature, petechial hemorrhages on conjunctival mucosa, swollen lymph nodes, anemia and cough. Changes in hematological, serum biochemical and histopathological parameters are good indicators for diagnosis of theileriosis. For this purpose a total of 100 blood samples from infected sheep as well as 50 blood samples from healthy sheep were collected on the basis of clinical examination and peripheral blood smears from different farms in and around Lahore. The collected samples were processed at Clinical Pathology Laboratory, Department of Pathology, University of Veterinary & Animal Sciences, Lahore. Hematological parameters were measured by automatic hematology analyzer & serum biochemical parameters were measured by using commercial kits by colorimetric methods using spectrophotometer. Histopathological changes were observed by making slides of tissue samples, and observed under microscope. Molecular confirmation of Theleria sp. was done by using Polymerase Chain Reaction. Finally the data obtained for hematological and serum biochemical parameters were analyzed by using Student's t test.
Previous studies on serum biochemical parameters and hematological parameters were mostly done in large ruminants. But there is little investigation available on the biochemical and hematological alterations of theileriosis in small ruminants. In this study blood samples taken from sheep were examined under microscope by making thin blood smears using Giemsa stain. Theileria piroplasms were seen in RBCs at 100x. Blood samples were also processed for PCR test. In all Theileria ovis positive samples 520-bp fragment was generated on gel by using primers TSsr 170F and TSsr 670R for sheep. All samples positive on microscopy were also positive by PCR. This study provides the base line data for molecular diagnosis of Theileria ovis in sheep in Pakistan. Hematological and biochemical parameters were evaluated in the sheep naturally infected with theileriosis while healthy sheep were selected as control. Hematological findings revealed a significant decrease (P<0.05) in RBC count, WBC count, Hb Conc. and PCV in infected animals as compared with healthy animals. Serum biochemical findings also revealed alterations in activities of enzymes and plasma proteins. A significant decrease in total proteins, albumin, glucose and creatinin and triglycerides was observed while significant increase (P<0.05) in ALT, AST, bilirubin was observed in affected animals as compared with healthy animals. A non significant increase in urea and cholesterol concentration was also observed in infected animals as compared to healthy animals. Different tissues were examined to study gross and histopathological changes. Liver was large, pale and friable. Prescapular lymph nodes were swollen and spleenomegaly was also seen. Kidney showed hemorrhagic spots and some were mottled. Histological examination of the lymph nodes revealed edema, widened intercellular spaces, parenchyma degeneration, massive lympholysis, widened sinuses at some areas and macrophages. Splenic nodules were sparse, diminished in size and lymphocyte depletion in follicles was prominent.In liver, mild infiltration of leukocytes around blood vessels, vacuolation in hepatocytes, increase in sinusoidal space and atrophy of hepatic cord was seen and hepatic cord was broken. In kidney, degeneration of tubular epithelium cells was seen. This study concluded that theileriosis in sheep was associated with some alterations in blood parameters and histopathological changes which could be useful in the diagnosis of ovine theileriosis.
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Pathological Investigations Of Theileriosis (T.Annulata) In Cattle In Disteict Lahore Punjab
Material type: Book ; Format:
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Publisher: 2014 Dissertation note: Theileriosis is very important protozoal disease in crossbred cattle. According to an
assessment, about 250 million cattle are endangered by this disease and millions of high milk
yielding cattle are at risk of exposure to disease. It acts as a bigger restraint on livestock
improvement and production in many developing countries (Nagore et al. 2004). Theileria
annulata is the main specie that causes high morbidity and mortality. It causes heavy economic
and production losses in cattle in tropical and sub-tropical regions. The recorded mortality rates
in cattle reached to 70% (Moor house et al. 2001).
Theileria species are intracellular obligate hemoprotozoan parasites. All Theileria species
are dangerous and cause disease but two of them are important for livestock. Theileria parva and
T. annulata produces diseases named as East Coast fever and tropical theileriosis in cattle
respectively. Genus Theileria has many other species like T. buffeli, T. taurotragi, T. velifera, T.
sergenti and T. mutans. These species cause infections in wild and domesticated ruminants.
Theileria species present in large and small animals show signs like fever, anorexia,
swelling of the superficial lymph nodes, dyspnoea, lethargy, progressive anemia, constipation,
diarrhea, lacrimation and nervous symptoms (Saeed et al. 2010; Irvin and Mawmachi 1983). A
pronounced rise in body temperature, reaching 40-41.5 °C is pursued by lacrimation, depression,
swelling of the superficial lymph node and nasal discharge. The characteristic sign of tropical
theileriosis is anemia and finally haemoglobinuria occur with heavy weight losses. The clinical
course of the disease alter from per acute to acute or sub-acute to chronic (Oliveira- Sequeira et
al. 2005). The disease is lymphoproliferative in its early phases resulting enlargement of lymph
nodes, later on enters lymph destructive phase which is associated with a pronounced
leukopenia. In the piroplasms phase in erythrocytes, the parasite becomes infective for the tick
(El-Deeb and Younis 2009).
Trans placental Bovine Tropical Theileriosis causing a deadly disease in a 3 day old
neonate cross bred calf and cerebral form of the disease (turning sickness) in a cow were
incriminated to T.annulata infection. It mainly depends upon the harmful effects of the T.
annulata on lymphoid tissues and susceptibility of the host (Sudan et al. 2012).
Theileriosis is prevalent in various regions of the world including Pakistan. It is transmitted by
Hyalomma species ticks. These ticks spread T. annulata which causes tropical theileriosis
(Durrani et al. 2009). The developmental stages of Theileria inside the Hyalomma ticks varies in
different shapes and forms (Hamed et al. 2011). Therefore to increase the milk and meat
production of cattle we can prevent the spread of the disease by controlling ticks
(Hekmatimoghaddam et al. 2012). The sufficient amount of Hyalomma ticks are found in warm,
commonly hard marshland and in central and Southern Europe, south west Asia and Southern
Africa having very long dry season. A toxin is produced in the adult ticks. This toxin produce
clinical signs of mucus membrane hyperemic and moist profuse eczema (Adam et al. 2000).
The sporozoites of Theileria enter into cattle host during tick feeding and they
immediately infect mononuclear leukocytes, these sporozoites develop into macroschizonts and
induce proliferation of the host cells. Macroschizonts constantly mature into microschizonts and
finally into merozoites, which are discharged from leukocytes. These merozoites attack
erythrocytes and mature into piroplasms, become available to ticks. Infective sporozoites,
injected during tick feeding, rapidly enter target cells, escape from the surrounding host-cell
membrane and differentiate to schizonts that interact with different host-cell components
(Dobbelaereand Rottenberg 2003). This interaction includes host cell signaling pathways that
regulate proliferation and cell survival (Chaussepied and Langsley 2011) and thus cause
blastogenesis and clonal expansion of predominantly T and B cells (Fawcett et al. 1982; Baldwin
et al. 1988; Spooner et al. 1989). Merozoites released from these schizonts subsequently infect
red blood cells and become trophozoites. Lymphocytic stage of Theileria (schizonts) is the cause
of many of the severe disease manifestations like lymphadenopathy, pyrexia, thrombocytopenia,
and panleukopenia (Homer et al. 2000). Marked anemia, anisocytosis, pikilocytosis, and
leucopenia were commonly observed in bovine theileriosis (Ceci et al. 1997). Cattle may survive
the disease, but recovery and convalescence may be protracted and incomplete, this leads to
permanent debilitation, loss of productivity and prolonged carrier state. (Shahnawaz et al. 2011).
Cattle with subclinical infection in endemic regions become carrier of piroplasms and act as a
source of infection for the vectors (Brown 1997; Brown 1990; Uilenberg 1995).
The diagnosis of theileriosis in acute cases is majorly done on clinical signs and Giemsa
stained blood smears of cattle but the detection of agent is not reliable and is almost impossible
in carrier stage. Advances in molecular biological techniques have resulted in the improved
detection, identification, and genetic characterization of many hemoparasites. Species specific
polymerase chain reaction (PCR) has been developed for the detection and identification of
various Theileria species and has been shown to have higher sensitivity and specificity compared
with serological assays and examination of Giemsa-stained blood smears (Bhoora et al. 2009).
Primers were derived from the gene encoding the 30-kDa major merozoite surface antigen for T.
annulata (Aktas et al. 2006).
Most of the previous studies on haematological parameters in T. annulata infection were
carried out on experimentally infected cattle (Sandhu et al. 1998; Singh et al. 2001). The present
investigation was conducted to study haematological parameters in cattle naturally infected with
T. annulata. Hematology has been broadly used in attempts to give information about disease
condition, performance problems and health in cattle (Rezaei and Naghadeh. 2006).
Hematological and sero-biochemical alterations are the indicators of severity of disease and are
considered to be good tools for the diagnosis, prognosis for effective therapy (Col and Uslu
2007; Nazifi et al. 2010b).
Lahore is one of the larger district in the Punjab province of Pakistan. Different cattle
breeds are reared by the people of the area for meat and milk production. The exact current
situation about the prevalence and pathogenesis of Theileriosis in the selected area is unknown.
The present study was conducted to screen cattle by finding schizonts or piroplasms in Giemsa
stained thin blood smears at slaughter house of district Lahore (Aktas et al. 2006) and later to
confirm through Polymerase Chain Reaction (PCR) (Chaisi et al. 2013) in order to implement
efforts and regulation to eradicate the spread of disease in the selected area. Data generated from
this study provided the latest status of Theileriosis, sex wise prevalence and its pathogenesis in
cattle population of Lahore. The study has also provided the necessary information to formulate
strategies for control of disease in the area. An investigation was also undertaken to ascertain the
changes in haematology as a result of Theileria annulata infection. These studies will help better
understanding of the pathogenesis and supportive therapy of this disease.
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