Pathological Impact of Johne’s disease in Cattle: A Review Article

Johne’s disease is an international healthiness problem affecting ruminants. It is caused by Myobacterium avium spp. paratuberculosis (MAP). It has serious production-limiting important and also caused significant cost-effective loss in flocks due to direct impact on delayed/reduced breeding, infertility, culling, mortality, and milk reduction. This disease is problematic to diagnose because of elongated incubation times. Proof of identity this disease subclinical can shed the organism as a source of infection for other herds; so, it is critical for control. The present study deals with the morphological (grossly, histopathologically and histochemically) characterization of the disease in cattle. The corpse appears hidebound with sunken eyes and with persistent and nonresponsive diarrhea. The necropsy of visceral showed gelatinization and outlying fat. Grossly chiefly pathological alterations in digestive tract such as severe congested of small intestine with marked thickening of its wall a combined with enlargement of mesenteric lymph nodes and gallbladder appear distension with severe thickening walls and blood mixed with bile. Histopathological examinations revealed severe infiltrations of inflammatory cells such as macrophages, lymphocytes, and epithelioid cells with multiple langhans giant cells in bowel layers and mesenteric lymph nodes with diffuse lepromatous reaction were observed in these lymph nodes and other organs like liver, tonsils and kidney. ـــــــــــــــــــــــــــــــــــــــــ


INTRODUCTION
Paratuberculosis is long-lasting emaciating disease characterized by granuloma in gut, lymphangitis, and lymphadenitis of regional L.N. It is an important infectious disease of domestic and wild ruminants worldwide caused severe commercial losses of ruminants characterized by alternating diarrhea at first and come to be more persistent and severe above (7) days or months lacking blood, mucus, epithelial debris, and wasting, limited weightiness loss (Roy et al., 2017), reduced milk secretion, increased counter of somatic cell, mastitis, reduced fertility (Elzo et al., 2009), roughening of hair coat, anemia with usual body temperature and food desire and when advanced affected animals become gaunt then die with terminal cachexia and dehydration (McAloon, et al., 2016). This disease have length incubation period ranged from 2-5 years, communal in cattle and not often exposed theoretical symbols before 2 years old infrequently cases (Windsor et al., 2010).

Clinical Signs:
Johne's disease Clinically characterized by pattern of chronic and enlightened emaciation with diarrhea, green feces, bubbly and without blood or mucus and its consistency .It expands for tiny times then diarrhea coming back with greater than before severity. The affected animals are sunny, alert and consume good during the course of disease progress while progressive state saw edematous fluid in submandibular, rectal thickened or corrugated mucosa may feel. Clinical signs of JD do not seem up to animals aged extra than 3 -4 years and some herds onset disease in 2-year-old

Gross And Histopathological Finding:
The infected animals appear thin or emaciated with advanced disease, independent edema and/or fluid in holes, grossly intestinal changed characterized by severe congested and marked thickening of its wall mostly appearance in distal small intestine while advanced cases extended from jejunum to colon with separate plaques presented in the disease at early also mesenteric lymph nodes enlargement (    Histopathological results of mesenteric and other regional LNs such as ileocecal enlargement and edematous with revealed multifocal lepromatous granuloma (epithelioid and giant cells in the paracortical areas with necrosis) that exchanged the cortex and medullary sinuses. he infected lymphatic vessels are bounded by lymphocytes and plasma cells and clusters of epithelioid cells in the lumen resulting in epithelioid granulomas which formed in wall then projected to lumen with improved records of real body macrophages full with cellular and karyorrhectic debris of apoptotic lymphocytes because the macrophages infested with mycobacteria have affinity to actuate apoptotic pathways, resultant in cell death (Koul et al., 2004). Pathological straining induce lesser levels of apoptosis comparative to minus pathogenical strains (Weiss et al., 2008). Also, it can labeled focal granulomas in liver, tonsil, other lymph nodes and frequently in kidney and lungs. liver histopathological examination showed overfilled of capillaries, portal vein, and hepatic vein in center of lobules, granulomatous &mononuclear cells infiltrate in portal tracts and trabeculae as shown in    2) Ziehl-Neelsen Stain used to detected clinical cases of JD when the MAP appear as clomps of small, strongly acid-fast bacilli in feces, intestinal mucosa or cutting of lymph node surface (Coelho et al., 2010).

3) Immunostaining methods can identify bacteria in
tissue samples but ABs may cross-react with other mycobacteria these methods used by taken biopsies of ileum and regional lymph nodes, M. avium ssp. paratuberculosis may cultivate on sum of specific culture media (Berghaus et al., 2006).

Difference between Tuberculosis, Paratuberculosis and Pseudotuberculosis:
The TB is chronic disease causative by Mycopacterium bovis and formed granuloma typical characterestic by necrotic center which is amorphous caseated granular fragments with loss of cellular feature also acid-fast bacilli are present, these necrotic area circled by epithelioid cells, lymphocytes, histiocytes, fibroblasts and Langhans' giant cells (Domingo et  al.,2014) while paratuberculosis diffused lepramatous and Corynebacterium pseudotuberculosis is a Gram+ and small bacillus, It is the causative agent of Caseous Lymphadenitis (CLA) in goats and sheep, while in cattle caused a disease identified as Oedematose Skin Disease (OSD) (Tejedor et al., 2008 and Nasr et al., 2019), pseudotuberculosis characterized by ulcerative granulomatous seemed in three clinical forms: cutaneous, mastitic and visceral and can observed mixed forms as shown in Fig.7 (Almeida et al., 2017).

Epidemiology and Transmission:
JD is prevalent in New Zealand and south-eastern states of Australia dairy cattle and recently impression on the Australian cattle industries recognized generally though ordinary cattle and sheep infected attendant cross-infections have been testified in strains of M paratuberculosis (Perez et al., 1996).
The transmission of Map depended on bacterial ability to survive within the environment, )Eppleston et al., 2014) recounted existence Type C Map strain wasn , t impacted by position but Type S strain hazard death was 2.3 times greater at dry neighborhood situates comparative with Australia heating place. The capacity to spore-like kinds formation mark it warmth resilient and facilitated escape within environs (Lamont et al.,  2012).
[ Evidence existence of diverse strain of Map in top soil, water, grass and manure of substantial significance for decline diffusion and exploration, as well as animal activities, farming carry out and of virulence influencing of strain on geographical distribution of these strains. Currently, whole genome sequencing show slight evidence for geographically distinct strains (Ahlstrom et al., 2014).
MAP is predominantly spread by the fecal-oral way when shed in huge quantities of organisms in the feces and intermittent in early stage of disease because it and upsurges in case of progresses disease and when infected animals are subjected to stress (Sweeney, 2011); virtual easiness of orally experimented transmission in young cattle and sheep.
The offspring of cattle can be born infected if dam in advanced phase of disease because it can shed MAP to variable grades in milk colostrum fecal contaminated of udder housed in polluted pens, and bacterial sums high during the first 2 months of the lactation for that the colostrum from infected cows is abundant risk for spreading of JD to Calves (Nielsen et al., 2008). The repetition of feeding collective colostrum or wasted milk spreading the infection to many calves during susceptible period of life, MAP may noticed in semen, saliva and milk (Slana et al., 2008). Calves greatest risk when exposure to the feces of adults infected with disease and transmitted the organism on fomites, other animals via aerosol unclean dust, the pathogen does not multiply outside a living host (Sweeney et al., 1992b).

Cross-species
have role in transmission, outbreaks and maintaining infection cycles of JD, even before molecular strain typing which have great improved knowledge about cross-species transmission of Map was accessible, epidemiologic indication suggest that natural communication between cattle and sheep was rare because cattle and sheep harbor diverse strains were host modified, the simplicity of separating Map from cattle & uneasy from sheep additional to existence of different strains evidence that milder sickness marked when sheep strains are pass on to cattle (Fridriksdottir et al., 2000).

Control:
Because the economic losses in both dairy and beef cattle caused by paratuberculosis disease (Windso, 2014). It must control its depended on population-level measures, applying hygienic measurment and vaccination (Konboon et al., 2018). Another risk factor outline of livestock in farm (Kirkeby et al., 2017). Losses of dairy farmer consist of before, during or after culling (McAloon et al.,2016), In beef cattle the losses be determined by farmer market (Webb Ware et al.,  2012), also killing rate of infection summarized (Kudahl et al., 2009).
The control programs have variable aims from lessening of clinical cases and/or MAP incidence Both healthy and 'test-and-cull' were essential to become stable the herd station, reduction of calf experience are most effective measure, followed by test occurrence (Camanes et al., 2018). Culling the progeny which infested cows considered as portion of the control strategy rate of in utero infection (Whittington et al., 2009). Pasture and grazing manage utilizing to lessor exposure of extensive grazed livestock (Eppleston et al., 2014).
Even nonappearance linked between MAP and human disease (Groenendaal et al., 2008).The zoonotic potential of M. paratuberculosis cannot be ignored, due to vital knowledge gaps in considerate its starring role of human disease (Waddell et al., 2016), its influence on communal healthiness do not measured or described (Waddell et al., 2016).
Immunization of ruminants revealed limitted of disease by decreased of clinical frequency and decreasing faecal shed of MAP (et al.,201470) but it isn't commonly used in cattle because threat interfering with ID testing for bovine tuberculosis (Bastida et al., 2011) . In contrast of Australian, Icelandic and Spanish sheep industries, inoculation widely used (Serrano et al., 2017).

Declaration of competing interest
On behalf of all authors, I hereby declare that no conflict of interest may interfere with the publication of the manuscript.