Pathoprevalence of infectious diseases of goat emphasizing on endoparasitic lesions at Dinajpur Sadar

This study was conducted to investigate the pathoprevalence of different infectious diseases of goat at Sadar upazilla of Dinajpur district in Bangladesh. Infectious cases were recorded with respect to breed, sex, age and season from Upazilla Veterinary Hospital and District Veterinary Hospital, Sadar, Dinajpur during July, 2014 to June, 2015 and diagnosis was made on the basis of clinical history, clinical examinations and common laboratory techniques with histopathological examination. A total of 2139 infectious diseases were founded and categorized by the causal agents where the highest prevalence was observed in mixed infectious diseases (46.06%) followed by viral diseases (28.93%), internal parasitic diseases (9.77%), external parasitic diseases (8.42%), bacterial diseases (3.00%), protozoal diseases (2.01%) and lowest was in fungal diseases (1.83%). The prevalence of infectious disease was significantly higher at Jamunapari (55.12%) than Black Bengal (44.88%). Female goats were more susceptible (54.32%) than male (45.68%). The prevalence was varied according to age and highest was in G-1 (45.48%) followed by G-2 (36.48%) and G-3 (17.68%). Summer season (33.60%) was common for infections followed by winter (33.51%) and rainy (32.89%). Most of the internal lesions were produced by the endoparasitic infections which were examined microscopically. These results indicate that, the prevalence of various infectious diseases in the goats was higher at Sadar, Dinajpur thus, there is a need for an appropriate control measures in order to prevent and minimize the loss caused by such diseases and this study may help to develop strategies against the infectious diseases of goat.


Introduction
Goat is one of the most important livestock species in Bangladesh and particularly useful for low-income farmers, landless labors and distress women, who can"t effort to rare cattle, hence, goat is called "the cow of poor people".In Bangladesh, at present, the approximate number of goats is 25.20 million (DLS, 2013).More than 90% of the total goat population comprises of Black Bengal Goat, reputed for their prolificacy, fertility, early sexual maturity, adaptability to hot humid conditions and superior quality meat and skin (Devendra and Burns, 1983;Hussain, 1993;Amin et al., 2001) and the remaining ones include the Jamunapari and their crosses.Goat usually suffer from many diseases of infectious and non infectious in origin (Singh and Prasad, 2008).However, some infectious diseases are presently become a great threat to these animals survival in Bangladesh.Infectious diseases are disorders caused by organisms such as bacteria, viruses, fungi or parasites.The occurrence of diseases is an important factor which influences the productivity and economy of goat farming.Diseases in goats result in mortality and morbidity losses, resulting in lower production.Several studies (Paliwal et al., 1978;Krishna et al., 1979;Chauhan et al., 1982;Chatterjee and Dey, 1992) have shown that on an average 20 % of kids and 10 % of adult goats die each year.Although, different studies have been carried out in various part of Bangladesh, but limited attempt have been taken to study the prevalence of infectious diseases in Dinajpur district.However, over the last some decades, there are tremendous changes in the climates, life styles of people and husbandry practices of livestock all over the Bangladesh.Considering these facts, present study was undertaken to study the prevalence of different infectious diseases of goats in Dinajpur district along with variation in different breed, their sex and environmental factors and line out the gross lesions of different organs with the merit of individual diseases with histopathology of affected organs collected from suspected goat with endoparasitic diseases.

Study area and period
The throughout investigation of goat diseases were performed in Sadar Upazilla and the detailed laboratory examination were carried out in the Department of Pathology and Parasitology under the Faculty of Veterinary and Animal Science (VAS) of HSTU, Dinajpur, Bangladesh during the period of July, 2014 to June, 2015.

Sampling and data processing
During this study period a total of 2,139 goats of different breed, sex and age were included in this study.The affected goats were recorded, organized under groups and seasons.Collected data were systematically arranged and analyzed statistically by using Statistical Package for Social Science (SPSS) software 17.0 version (T-test and Chi-square test).

Clinical examination
The general clinical findings are noted during submitting and registration in patient register for diagnosis and treatment purposes.The characteristic clinical features were recorded during the physical visit and the farmers and owner complains were also emphasized.Examination of different parts and systems of the body of sick animals were performed by using the procedure of palpation, percussion, auscultation, needle puncture and walking of animals.

Coprological examination
Coprological examination was performed making a direct smear in glass slide and examined under microscope using various objects.

Pathological Examination
The dead goats were received for necropsy findings using a standard method.Gross morbid lesions were recorded and the samples of affected organs were collected carefully, preserved at 10% formaline, processed for histopatholgical examination (Luna, 1968) and stained with H&E stain with a standard method.The slides were examined under microscope and findings were recorded carefully (Luna, 1968).

Diagnosis of diseases
The diseases of goats were diagnosed basically based on interlinked epidemiological factors (breed, sex, age and season), general clinical findings, coprologic and pathologic features during examination.

Epidemiological Findings
Table1 have shown that, the infectious diseases found throughout the study were categorized according to the causal agents into viral, bacterial, protozoal, fungal, external parasitic, internal parasitic and mixed infectious diseases and the highest prevalence was observed in mixed infectious diseases (46.06%) followed by viral diseases (28.93%), internal parasitic diseases (9.77%), external parasitic diseases (8.42%), bacterial diseases (3.00%), protozoal diseases (2.01%) and lowest was in fungal diseases (1.83%).PPR (28.56%) was most commonly founded infection among the viral diseases.In bacterial diseases prevalence of infectious arthritis was (1.50%) was higher than others.In the category of fungal infection, dermatophytosis (1.83%) was common.Under the protozoal infection (1.59%) cases of coccidiosis was founded, among a large number of external parasitic diseases (5.75%) cases of lice infestation which was higher and from internal parasitic diseases the higher prevalence was in mixed internal helminth (9.12%).In the mixed infectious diseases (17.67%) cases of upper respiratory tract infection was most common.

General clinical findings 3.2.1. Viral diseases
In Pesti des Petits Ruminants (PPR), common clinical findings were high fever, sneezing, coughing, dyspnoea, serous or mucopurulent ocular and nasal discharge, dullness, erosive stomatitis, diphtheretic plaques on oral mucosa, diarrhea mixed with blood and mucus .In Contagious Ecthyma (Sour Mouth) the clinical sign were pastular and scabby lesions on muzzle, nostrils, lips, coronets, ears, anus, vulva, prepuce and sloughing of the affected epidermal layers.

Bacterial diseases
Infectious Arthritis characterized by swelling in one or more joints, lameness, fever, occasional chills.Foot Rot revealed with the clinical signs of lameness with there were elevated body temperature, swelling of the foot, and separation of the skin.In Tetanus common signs were muscle and limbs stiffness, drooping eyelids, lock jaw, erect ears and tail, changed voice and inability to eat or drink, unsteady gait and convulsion.Death with protrusion of tongue.

Fungal diseases
Dermatophytosis (Ringworm) was signed by circular lesions with incomplete alopecia and thickened, flaky, skin with gray/white crust formation in the affected areas.

Protozoal diseases
Coccidiosis was diagnosed by the signs of persistent diarrhea containing blood and mucus with imappetance, weight lose, dehydration, rough hair coat and straining attempt to pass feces Babeiosis was recognized by dark reddish brown urine with high fever, imappetance, dyspnoea, and anaemia.

External parasitic diseases
Lice Infestation was manifested by scratching, rubbing, biting of infested areas and broken fibers.Tick infestation were characterized with the formation of papules, pustules, ulceration and alopecia particularly in the skin of ears, face, neck, groin, digital limbs, tail and other areas of the body.Scabies was characterized with severe etching, varying degrees of dermatitis with extensive hair loss around the muzzle, eyes, and ears; lesions on the inner thighs extending to the hocks, brisket, underside and axillary region.Myiasis was characterized by maggot found in the affected area with oozing of blood from the wound.

Internal parasitic diseases
Gid was diagnosed by the clinical signs of circling, head shaking, soft skull, skin over the bone become shrinkage and cyst identification.The clinical signs of mixed internal helminth infestation were diarrhoea, dehydration, anorexia, emaciation, abdominal distention and pale visible mucous membrane to a large extent as where a very few infected goats suffered from "bottle jaw".

Mixed infectious diseases
Upper respiratory tract infection was manifested by clinical signs ofnasal discharge, sneezing, coughing, dyspnoea, elevated temperature and loss of appetite.The nasal discharge came out from one or both nostrils and the nasal passages were blocked in most cases.Pneumonia was recognized by coughing, rapid breathing, dyspnoea, nasal and ocular discharge, moderate fever, imappetance, weight loss, lethargy and dullnes.In infectious diarrhoea, clinical signs were profuse amounts of liquid feces with dehydration, weakness, depression and recumbence.Sometime feces foul smelled containing blood, fibrin and copious amounts of mucus.Clinical signs of metritis were foul smelling vaginal discharge without pus frequently accompanied by fever.In dermatitis signs were mild erythema, scaling and alopecia, in some extend mild pyoderma founded.Mastitis was characterized by the signs of clots and/or blood in the milk, reduced milk yield, hot, red, swollen, hard and painful udder.Fever and anorexia was common.In urinary tract infection common clinical signs were frequent urination, straining to urinate, blood in the urine, excessive licking of the genitals.Infectious Keratoconjunctivitis (Pinkeye, Infectious ophthalmia) was revelead by clinical sign of conjunctivitis, lacrimation with varying degrees of corneal opacity, ulceration and blepharospasm.

Pathological lesions of endoparasitic diseases
In ascariasis, grossly there was pale spot which extended shortly in liver parenchyma (Figure1) and microscopically we found parasitic granuloma composed of longitudinal section of larva in liver parenchyma surrounded by lymphocytic proliferation with fibrosis.Grossly nodule formation was commonly observed in the mucosa at any point from the pylorus to the anus at O. columbianum infection.Nodules were hard, raised, and slightly yellowish in color (Figure 1, B).
In fascioliasis the gross pathological changes of the liver in chronic fascioliasis were increased size of the organ due to inflammatory changes in the parenchyma and fibrosis of the bile ducts containing adult flukes.In acute form, the livers were slightly swollen or enlarged with rounded edges and the color became paler than normal with numerous small and large hemorrhagic patches scattered over the parietal surface of all the lobes (Figure 1,C) and microscopically, there were multiple cross section and longitudinal section of adult worm, diffused fibrous connective tissue proliferation which bring pressure atrophy to the adjacent hepatic cells resulting hepatic chirrhosis with mononeuclear inflammatory and lymphocytic proliferation throughout the liver debris of worm in the intrahepatic bile duct with thickened blood vessel due to fibrosis (Figure 2, E).Hydatid cysts were fluid filled cysts, some up to the size of oranges or grapefruits were founded in the lungs and livers and also in the peritoneal cavity (Figure 1, E and F) and microscopically there were hydatid scolex in the central vein surrounded by fibrosis with severe scattered of inflammatory cells surrounding the fertile cyst and lobular destruction with reactive cell infiltration finally completely autolization of liver (Figure 2, D).In case of lung, microscopically we found multicystic lung and cysts containing several scolices with germinal lining with fibrosis in lung parenchyma causing destruction of pulmonary alveoli, and in the spleen there were scolex in the parenchyma with huge reactive cell infiltration with diffused edema in trabicule (Figure 2, F).
In schistosomiasis the commonly founded lesions were, the liver was firm and pale in color and microscopically there were ova granuloma in the liver with intense infiltration of mononuclear and polymorph nuclear cells in the portal tract and fibrosis around the egg.In Spleen there was hemosiderosis throughout the spleenic parenchyma (Figure 2, C).

Discussion
Infectious diseases are a global problem and considered as a major obstacle in the health and product performance of livestock specially goats (Nath, 2014).In recent study, a total of 2139 goat records were collected throughout the period from the DVH office and UVH office of Dinajpur.This study found highest proportional incidence rate in mixed infectious disease (46.04%) followed by viral diseases (28.93%), internal parasitic diseases (9.77%), external parasitic diseases (8.42%), bacterial diseases (3.00%), protozoal diseases (2.01%) and lowest prevalence were in Fungal diseases (1.83%).The result of recent study is more or less similar to Amin (2015) who mentioned viral disease (20.02%), bacterial diseases (17.88%), fungal disease (1.44%), Endo-parasitic diseases (29.27%), ectoparasitic diseases (29.27%), protozoal diseases (4.37%) and others (19.33%) and Alam et al. (2015) resulted as viral diseases (11.47%), bacterial diseases (6.55%), (25.20%) endoparasitic diseases and (12.50%) ectoparasitic diseases but slight difference from Pervez et al. (2014).The findings of the present study are similar in most cases with the earlier reports but the little more variations might be due to the differences in the sample size, period and place of study, collection method of samples, animals breed and categorization of infections, climatic and managemental factors.Prevalence of infectious disease were significantly higher (at p<0.005) in Jamunapari (55.12%) than Black Bengal (44.88%) which is not in agreement with Nath et al. (2014) who recorded the prevalence of infectious disease was highest at Black Bengal breed (64.23%) and lowest in Jamunapari cross (57.39%), although it is tough to explain the main cause of overall variation but it may be said that, as the native breed, Black Bengal are more resistance against these infectious diseases.Prevalence of infectious diseases in relation to sex revealed that there were significantly higher females (54.32%) (at P<0.05) infected than the male (45.68%) similar record was found in Nath et al. (2014), Parvez et al. (2014) and Ali et al. (2011).The reasons for higher prevalence of infection in the females can"t be explained exactly but it might be assumed that the alternation in the physiological condition of the females during pregnancy, lactation and parturition (hormonal influences) as well as stress leading to immune suppression may be associated with this phenomenon (Lloyd, 1983).It was revealed that age of the goats had insignificant effect on infectious diseases.Prevalence of infectious diseases in goats was relatively higher in G-1 i.e. the age group of 0-12 months (45.48%) followed by lower in G-2 aged with 13-24 months (36.84%) and G-3 aged >24 months (17.68%) respectively.The findings of the present study similar to Nath et al. (2014), andParvez et al. (2014).Although it is very difficult to explain exactly the frequent occurrence of infections in all groups but it may be assumed that the exhausted immune system of adults and underdeveloped immune system of youngs may be responsible for more or less equal prevalence of different infections in all age groups.
From the present study it was revealed that seasonal variation had insignificant effect on infectious diseases.Prevalence of infectious diseases in goats were relatively equal in all the seasons like rainy (32.89%), winter (33.51%) and summer (33.60%), this prevalence is in agreement with the findings of Nath et al. (2014) who resulted the occurrence of various infectious diseases were distributed in rainy season (36.43%) followed by winter season (34.94%) and summer season (28.62%).Season wise prevalence indicated that, although the infections were more or less equal in all seasons but in winter season goats were more susceptible for infectious diseases due to the animal gather together in excessive cold environmental condition, resulting easy transmission of infections along with improper management, highest percentage of diseases was found in winter season.

Conclusions
Various Infectious diseases now become a global problem and considered as a major obstacle in the health and product performance of livestock specially goats.For the prevention and control of the diseases, a thorough knowledge about the occurrence of diseases, their epidemiology, pathogenesis and pathology of the diseases are essential.The present pathological investigation and prevalence study on to the infectious disease of goat at Sadar Upazilla in Dinajpur district of Bangladesh and from all these findings it may be concluded that these various infectious diseases appeared as an important cause for hindering the goat rearing in Dinajpur area.Regular vaccination and proper surveillance and monitoring can eradicate those diseases.Veterinary inspection should pay attention for these all farm animals to detect the infectious diseases that may hamper the production of animals and make loss of the farmer.Further studies should be find out the source, distinctive causal agent and histopathology of other infections more than the endoparasitic lesions to find out effective control strategies against specific infections.

Figure 1 Figure 2 .Figure 2 .
Figure 1. A. Ascariasis characterized by showing pale spot which extended shortly in liver parenchyma, B. O. columbianum infection showing hard, raised and yellowish nodule formation in themucosa of colon, C. Fascioliasis characterized with acute inflammation with fibrosis of liver , D. adult fluke comes out from liver in fascioliasis, E. Hydatidosis disease signed with grape shaped cyst formation in the lung and F. Cystic degeneration in the liver parenchyma in Hydatidosis , Talukde et al. (2010) and Blutke et al. (2010) and the microscopic findings were similar with the findings of Okoye et al. (2015), Abraham and Jude (2014) and Borai et al. (2013), Se´adawy et al. (2012), Blutke et al. (2010), Habtamu et al.