Veterinary World, EISSN: 2231-0916 Available at www.veterinaryworld.org/Vol.6/Oct-2013/6.pdf RESEARCH ARTICLE Open Access

Aim: To conduct detailed pathomicrobial studies on Salmonella Gallinarum infection in broiler chickens. Materials and Methods: Bacteriological and pathological studies were conducted on 134 dead poultry birds collected from 23 different farms suspected to be infected with S. Gallinarum. Results: Mortality pattern revealed that maximum mortality occurred in 1-2 week aged birds. Out of 23 Salmonella isolates, 19 samples were identified as S. Gallinarum (9, 12) and 4 samples as Salmonella Enteritidis (9, 12: gm). Isolates were found to be most sensitive to Polymyxin B (100%). The present study also showed re-emergence of chloramphenicol sensitivity (83.33%). Pathological lesions observed were bronze discolouration of liver, splenomegaly and necrotic foci on liver, spleen and heart. Microscopically, liver and spleen revealed aggregation of heterophils, lymphocytes and macrophages, nonsuppurative myocarditis, fibrinous pericarditis, interstitial nephritis, necrotic enteritis and serofibrinous pneumonia. Conclusion: It was concluded that S. Gallinarum 9, 12 was the main serotype causing Salmonellosis in poultry birds. Polymyxin B was the most sensitive drug (100%) for Salmonella infection along with re-emergence of chloramphenicol sensitivity for Salmonella (83.33%) infection.


Introduction
. Mahajan et al. [8] studied major diseases affecting broiler chickens during [1987][1988][1989][1990] in Haryana and Fowl typhoid, an acute septicaemic disease of observed that fowl typhoid was the one that caused avian species that is caused by Salmonella Gallinarum maximum mortality (10.54%) and accounted for the [1] affects all age groups of chickens.Morbidity is high second highest number of outbreaks (198) after E. coli among all age groups of the birds, whereas mortality (266).Control of fowl typhoid is difficult [9] due to may range widely from 10% to 90% [2].Maintaining a endemicity of the disease, facultative intracellular disease free status is a challenging exercise due to the nature of causative organism, both vertical [10] and rapid expanding nature of the industry.This is indicated horizontal [11] modes of transmission, presence of by the fact that a number of Salmonella outbreaks carrier stage and multiple drug resistance.The reported in the world are a result of injudicious widespread and indiscriminate use of antibiotics in the introduction of infected birds [3].Thus, poultry treatment of poultry diseases has lead to an increase in industry is facing great setbacks due to frequent the number of resistant Salmonella strains isolated outbreaks of salmonellosis [4].Since its discovery, [12].Antimicrobial resistance is a global public health many efforts have been made to control and prevent the concern [13].occurrence in commercial poultry farming.However, Thus, the present study aimed to evaluate the outbreaks of Salmonellosis still remain a serious economic pathological and bacteriological findings of fowl problem in countries where control measures are not typhoid and to understand their antibiogram.efficient or in those areas where the climatic conditions

Materials and Methods
favour the environmental spread of these microbes [5].The economic losses are chiefly due to morbidity, Postmortem examination was conducted on 134 mortality, reduced growth rate, reduced feed conversion dead poultry carcasses received from 23 different efficiency, drop in egg production, decreased fertility farms and were divided into three groups on the basis of and hatchability [6].The endemicity of the disease has their age i.e.Group I (0-1 wks), Group II (1-2 wks) and been established in India including Haryana where the Group III (2-3 wks) to study the mortality pattern.The infection was first detected in Gurgaon area in 1981 study was conducted in the Department of Veterinary Pathology, College of Veterinary Science, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana.Gross pathological changes like swollen, congested liver with bronze discoloration, enlarged spleen, multiple necrotic foci on spleen and Institute, Kasauli, Himachal Pradesh, India for further liver; and multiple white nodules on heart with distortion serotyping. in shape suggest that carcass can be suspected to be Pathological findings: All the organs and tissues of the infected with Salmonella Gallinarum.Clinical signs carcasses were examined critically for gross changes and history regarding vaccination was collected from during postmortem examination and the lesions owners which showed that infected birds exhibited observed were recorded.The formalin fixed tissues acute illness, ruffled feathers, inappetance, difficulty in were processed and stained using routine haematoxylin breathing, reluctance to move and watery to mucoid and eosin staining method [16].yellowish diarrhoea which further confirms our

Results and Discussion
assumption of Salmonellla Gallinarum infection.The birds were vaccinated against Marek's disease (on 0 Mortality pattern: Age-wise mortality due to Salmonella day), Newcastle disease (at 5 days and 22 days) and spp.revealed maximum mortality in group II followed Infectious bursal disease (at 14 days) and were by group I (Fig. 1).These results are in agreement with maintained under standard managemental practices.
previous reports [17].It is likely due to the fact that During postmortem examination, blood from the chicks are not fully immunocompetent when they are hearts of carcasses was collected with help of sterilized below 2 weeks of age because of a lower percentage of syringes for bacteriological examination.Different CD4+CD8-in the thymus; CD4-CD8+ and organs were examined critically for gross lesions and CD4+CD8+ in the spleen [18] as well as due to absence were collected under aseptic conditions for bacterioof protection from maternal antibodies at 1-2 weeks of logical isolations.Tissue pieces of heart, liver, lung, age.spleen, intestine, pancreas, proventriculus, bursa of fabricius and kidney were collected in a 10% buffered formalin for histopathological examination.were subjected to various biochemical tests for further characterization [14].Isolates were subjected to in-Salmonella characterization: Out of 23 Salmonella vitro drug sensitivity test using 20 antimicrobials by the isolates sent for serotyping, 19 samples were identified disc diffusion method as suggested by Bauer et al. [15].
as Salmonella Gallinarum (9,12) and 4 samples as Salmonella Enteritidis (9,12: gm).Salmonella Serotyping of the isolates: Organisms positive for Salmonella spp.were sent to National Salmonella and Gallinarum and Salmonella Enteritidis share a Escherichia Centre (NSEC), Central Research common immunodominant surface antigen (O9), such that S. Enteritidis preinfected poultry were protected bleb formation on cell wall and morphological changes against colonization with Salmonella Gallinarum.This in the cytoplasm [27].The varying degree of resistance shows that coexistence of S. Gallinarum and S.
and sensitivity to chemotherapeutic drugs has also Enteritidis in poultry prompts competition as a result of been reported by Sujatha et al. [28].High prevalence of the shared immunodominant O9-antigen which nalidixic acid resistance among Salmonella Gallinarum generates cross-immunity [19].Several published was also reported by previous workers [25].In the studies in other countries have reported antimicrobial present study, the resistance to above mentioned resistance in Salmonella [20][21][22].Antibiogram patterns antibiotics might be attributed mainly to the frequent of isolates in the present investigation showed varying and indiscriminate use of these antibiotics for degree of sensitivity to the chemotherapeutic agents treatment, prophylaxis and as feed supplements.tested (Table -1).Salmonella spp.were found to be Pathological studies: During necropsy examination most sensitive to polymyxin B (100%) which was in carcasses of the Salmonella infected birds appeared agreement with the findings of Kavitha et al. [23] jaundiced.followed by amoxicillin, amoxicillin sublactam, Liver: Grossly, the liver appeared swollen, congested enrofloxacin, doxycycline hydrochloride (91.66%).In along with bronze discoloration (Fig. 2).Microscopiour study, Salmonella spp. was found to be resistant to cally, hepatitis characterized by leucocytic infiltration nalidixic acid (84%).The Salmonella isolates in India at perivascular areas along with hydropic vacuolation from 1996-99 and 2001 were reported to be 100% in hepatocytes, multiple necrotic foci was noticed with chloramphenical sensitive and sensitivity of 79% was Kupffer cell hyperplasia.Few areas displayed necrosis also reported in 2000 [24].The present study also of hepatocytes, with focal aggregation of heterophils, observed chloramphenical sensitivity of around lymphocytes and macrophages (Fig. 3).Similar 83.33%; similar findings have been reported by degenerative, necrotic and infiltrative lesions have Taddele et al. [25].This re-emergence of chloramphenicol been reported earlier [28][29][30].sensitivity could be attributed to the limited use of this antimicrobial during the last decade in India [26].
Heart: The cardiac lesions consisted of mild to Highest sensitivity of Salmonella to polymyxin B moderate congestion and hemorrhage.In few cases, might be due to the cationic action of polymyxin B on multiple white nodules with distorted shapes were cell membrane of susceptible bacteria where it causes observed on the heart (Fig. 4).Histopathologically severe degeneration and fragmentation of myocardial bursal follicles along with interfollicular fibrosis.Loss muscle fibres (non suppurative myocarditis) was observed of lymphoid tissue from follicles and degeneration of in most of the cases with leucocytic infiltration (Fig. 5).
bursa of fabricius has been reported by Garren and Fibrinous pericarditis with infiltration of heterophils, Barber [33].These workers suggested that changes in lymphocytes and macrophages was also observed in bursa resulted from adverse physiological conditions some cases.Similar findings have been reported by like anorexia, dehydration, anaemia etc. Msoffe et al., [31].
Poventriculus: The proventriculitis was characterized Spleen: There was splenomegaly along with multiple by congestion, mucosal degeneration along with necrotic foci on the surface.Microscopically, there was infiltration of heterophils and lymphocytes in mucosa severe depletion of lymphoid cells in white pulp along extending up to serosal layer in some cases.Mucosal with reticuloendothelial cell hyperplasia (Fig. 6).
glands were atrophied due to leucocytic infiltration in a Besides this in a few cases, a number of secondary few cases.There was degeneration of proventricular lymphoid follicles was noticed.Similar histopathologlands and lumen was filled with detached epithelial gical changes including focal necrosis, reticulo mass.The microscopic changes in proventriculus were endothelial cell hyperplasia and secondary lymphoid similar to those reported by Rao et al. [34].follicles have been reported by Shivaprasad [30].

Conclusion
Intestine: Grossly, catarrhal enteritis was evident in S. Gallinarum 9, 12 was mainly involved in some cases characterized by thick slimy mucus causing Salmonellosis in poultry birds tested in the exudate on mucosal surfaces in the lumen of intestine.
present study.In some of the cases S. Enteritidis was Histopathologically there was desquamation of also isolated.Polymyxin B was the most sensitive drug mucosal epithelium resulting in denuded villi and (100%) for treating Salmonella infections.Surprisingly, lumen was filled with necrotic mass (Fig. 7).Secretory our study also revealed that Salmonella infections are glands were atrophied at some places due to severe also highly sensitive to chloramphenicol .infiltration of heterophils and mononuclear cells.

Recommendations for farm owners
Goblet cell hyperplasia and focal fibroblastic connective tissue proliferation between the glands was Because polymyxin B was found to be the most present in many cases.Giannella [32] reported that sensitive drug for Salmonella infection in the present Salmonella induced diarrhoea is multifactorial.The study, we recommend the drug for treatment of onset of fluid secretion is preceded by a massive influx salmonellosis. of inflammatory cells leading to release of prostaglan-

Table - 1
. In-vitro chemotherapeutic drug sensitivity (% sensitivity) of Salmonella spp.isolated from visceral organs and heart blood