Diagnosis of Johne's Disease
DIAGNOSIS OF JOHNE’S DISEASE IN CATTLE
INTRODUCTION Worldwide, Johne’s disease (JD), caused by Mycobacterium avium subsp. paratuberculosis, is one of the most prevalent and economically important diseases of livestock and other ruminants. However, it is largely unnoticed on the dairy and its symptoms may be unfamiliar to most dairymen. Johne’s disease (JD) was first diagnosed in India in 1913 at Hissar followed by reports of JD throughout the country with incidence ranging from 1.78 to 1.9%. Latest reports reveal an increased seroprevalence of JD ranging from 15% to 78%. Larson et al, (1978) showed that controlled clinical vaccination trial with whole cell bacterin reduces incidence of clinical JD. van Schaik et al, 1996 showed that vaccination is cost-effective due through reducing the culling rate of clinically affected cattle. National Animal Health Monitoring Systems (NAHMS) study, Dairy 2007, shows that 68.1 percent of U.S. dairy operations are infected with Mycobacterium avium subsp. paratuberculosis (MAP) and also suggests that at least one out of every four U.S. dairy operations may have a relatively high percentage of Johne’s-infected cows in their herds. Although most U.S. beef herds are not infected with Johne’s disease, it is estimated that eight out of 100 U.S. herds may be infected with this devastating disease. The estimation of herd in Netherlands was found to be 55% prevalence (Muskens et al 2000) and in Denmark the figure was 47% (Nielsen et al 2000).
Johne’s disease (JD) or paratuberculosis in animals is incurable, chronic wasting and debilitating disease characterized by weight loss and profuse diarrhea. Paratuberculosis is principally a disease of ruminants but MAP can also infect non ruminant animal species (pigs, dogs, horses, cat etc) including free ranging animals (Blue bull, deer, rabbits) and primates (Chiodini et al., 1984). Johne’s disease adversely affects animal productivity leading to huge economic
INTRODUCTION Worldwide, Johne’s disease (JD), caused by Mycobacterium avium subsp. paratuberculosis, is one of the most prevalent and economically important diseases of livestock and other ruminants. However, it is largely unnoticed on the dairy and its symptoms may be unfamiliar to most dairymen. Johne’s disease (JD) was first diagnosed in India in 1913 at Hissar followed by reports of JD throughout the country with incidence ranging from 1.78 to 1.9%. Latest reports reveal an increased seroprevalence of JD ranging from 15% to 78%. Larson et al, (1978) showed that controlled clinical vaccination trial with whole cell bacterin reduces incidence of clinical JD. van Schaik et al, 1996 showed that vaccination is cost-effective due through reducing the culling rate of clinically affected cattle. National Animal Health Monitoring Systems (NAHMS) study, Dairy 2007, shows that 68.1 percent of U.S. dairy operations are infected with Mycobacterium avium subsp. paratuberculosis (MAP) and also suggests that at least one out of every four U.S. dairy operations may have a relatively high percentage of Johne’s-infected cows in their herds. Although most U.S. beef herds are not infected with Johne’s disease, it is estimated that eight out of 100 U.S. herds may be infected with this devastating disease. The estimation of herd in Netherlands was found to be 55% prevalence (Muskens et al 2000) and in Denmark the figure was 47% (Nielsen et al 2000).
Johne’s disease (JD) or paratuberculosis in animals is incurable, chronic wasting and debilitating disease characterized by weight loss and profuse diarrhea. Paratuberculosis is principally a disease of ruminants but MAP can also infect non ruminant animal species (pigs, dogs, horses, cat etc) including free ranging animals (Blue bull, deer, rabbits) and primates (Chiodini et al., 1984). Johne’s disease adversely affects animal productivity leading to huge economic