CAMPYLOBACTERIOSIS

INTRODUCTION

Campylobacter is a helical shaped, non- spore forming, gram negative, microaerophilic, non- fermenting bacterium forming bacterium forming motile rods with a single polar flagellum, which are also oxidase- positive and grow optimally at 37 to 42 degrees. When exposed to atmospheric oxygen, Campylobacter jejuni (C. jejuni) is able change in coccal form.

The burden of foodborne diseases, including Campylobacteriosis, is substantial; every year almost 1 in 10 people fall in and 33million of healthy life years are lost.

The high incidence of campylobacter causes diarrhea, as well as its duration and possible complications, makes it highly important from a socio-economic perspective. In developing countries, campylobacter infections in children under the age of 2 years are especially frequent, sometimes resulting in death.

Campylobacter are mainly spiral-shaped, “S”- shaped, curved, rod-shaped bacteria. Currently, there are 17 species and 6 subspecies assigned to the genus campylobacter, of which the most frequently reported in human diseases are

• C. jejuni (subspecies jejuni)
•  C. coli.
• Other species such as C. lari and C. upsaliensis have also been isolated from patients with diarrhea disease, but are reported less frequently.

THE DISEASE

Campylobacteriosis is the disease caused by the infection with campylobacter.

• The onset of disease symptoms usually occurs 2 to 5 days after infection with bacteria, but can range from 1 to 10 days.
• The most common clinical symptoms of campylobacter infection include diarrhea (frequently bloody), abdominal pain, fever, headache, nausea, and/or vomiting. The symptoms typically last 3 to 6 days.
• Death from Campylobacteriosis is rare and is usually confined to very young children or elderly patients, or those already suffering from another serious disease.
• Complications such as bacteremia, hepatitis, pancreatitis and miscarriage have been reported with various degrees of frequency. Post-infection complications may include reactive arthritis and painful inflammation of the joint that can last several months) and neurological disorders such as Guillain-Barre syndrome, a polio like form of paralysis that can result in respiratory and severe neurological dysfunction in a small number of cases.

SUSCEPTIBLE HOSTS

The C.foetus is pathogenic to cattle, buffalo, sheep, goat, pregnant guinea pigs, hamsters and man.

SOURCES AND TRANSMISSION

• Campylobacter species are widely distributed in warm blooded animals.
• They are prevalent in food animals such as poultry, cattle, pigs, sheep and ostriches; and pets, including cats and dogs.
• The bacteria have been found in shell fish.
• The main route of transmission is general believed to be foodborne, via undercooked meat and meat products, as well as raw or contaminated milk.
• Contaminated water or ice is also a source of infection.
• A proportion of cases occur following contact with contaminated water during recreational activities.
• Campylobacteriosis is a zoonosis, a disease transmitted to humans from animals or animal products. Most often, carcasses or meat are contaminated by campylobacter from feces during slaughtering. In animals, campylobacter seldom causes disease.
• The relative contribution of each of the above sources to the overall burden of the disease is unclear but consumption of undercooked contaminated poultry is believed to be a major contributor. Since common source outbreaks account for a rather small proportion of cases, the vast majority of reports refer to sporadic cases, with no easily discernible pattern.
• Estimating the importance of all known sources is therefore extremely difficult. In addition, the wide occurrence of campylobacter also hinders the development of control strategies throughout the food chain. However, in countries where specific strategies have been put in place to reduce the prevalence of campylobacter in live poultry, a similar reduction in human cases is observed.

PATHOGENESIS

The ovum is fertilized following the initial exposure to infection with the infected semen. The organisms multiply in the cervix and reach the uterine horn and oviduct 7-14 days later. In the early abortion up to 4^th month of gestation, the embryo is expelled along with fetal membranes. On the other hand, in abortion occurring after the month of gestation, the placenta is retained. The organism used to damage the cilia of epithelial lining of oviduct thereby interferes with fertilization.

In the bovine cervix, organisms metabolize amino acid and other organic acids and are protected the mucus from phagocytosis. During the luteal phase, the uterus of the cow becomes extremely susceptible to infection by bacteria (Rowson et al, 1953), thus the organism migrates from the cervix to the uterus during this phase. During pre-implantation period, the embryo essentially requires oxygen and if affected due to drop in dissolved oxygen tension of its environment (Whitten, 1971). Campylobacter has an obligatory respiratory mode of metabolism and can rapidly lower the dissolved oxygen tension of the nutrient medium (Wane, 1980). Campylobacter impairs the supply of oxygen and probably other nutrients required for the implantation of embryo and thus retard its implantation and development (McLaren and Bowman, 1973). 

CLINICAL FINDINGS

• Abortion is the chief sign of infection
• Susceptible cows when served by infected bull, fertilization occurs but is followed by early embryonic death.
• Retention of placenta is common in late pregnancy.
• Pyometra is rarely observed.
• Slight mucopurulent discharge and during heat period the mucus is cloudy with several clots and increase in amount.
• After 3-4 months, the acute phase subsides and chronic form ensues.
• Acute form occurs in heifer and cow which are exposed to infection for the first time.
• The recovered cows develop partial immunity against re-infection.

IMMUNITY

Vaccination has been shown to be effective in the prevention of C.fetus subspecies fetus abortion in sheep flock (Storz et. al. 1966). After the first abortion the ewes develop immunity for some time, but the males remain carriers.

C. fetus subspecies veneralis infection in cattle population that breed naturally is self- limiting but carrier state exists in bulls and thus infection may continue susceptible virgin heifers and newly introduced stock. These animals should therefore be vaccinated.

LESIONS

Infection of the uterus and oviduct persist for two months and thereafter infection gets eliminated and in third month it is confined to cervix and vagina. There is catarrhal inflammation of the cervix and vagina there is sign of mild endocarditis and necrosis of cotyledons. Cotyledonary changes may also include edema of intercotyledonary areas and hemorrhage of cotyledons. The endometrial changes are comprised of lymphocytic and plasmocytic reactions.

In the bull, there are no appreciable histological changes in the prepucial sac. Changes lie in the semen. The susceptibility of older bulls has been associated with an increase in size and, number of crypts in the epithelium of penis which provide an ideal environmental condition for the organism.

DIAGNOSES

Breeding history, abortion, temporary infertility or delayed conception associated with frequent and irregular estrus is indication of the presence of the disease. But, for a positive diagnosis, the following laboratory procedures are necessary;

• Demonstration of the organism in the gram stained smear prepared from the stomach contents of aborted calf or lamb.
• Demonstration of the organisms in the smear prepared from the contents of cotyledons or vaginal mucus.
•  Isolation and identification of the organism by cultural method. Vaginal mucus is the ideal material for culture. For the collection of vaginal mucus is very important. Owing to the susceptibility of the organism to the atmospheric oxygen level, the sample must either be spread over the surface of plates of solid selective media or be given protection if more than 6 to 8 hours’ time is required for delivery at the laboratory. A suitable method is to the sample in selected tubes kept at 79 degree centigrade. In dry ice. Vaginal mucus may be shown on blood agar plates and slopes to which a few ml. of defribinated blood is added after inoculation. The organism can also be grown in the allantoic fluid of 7 to 9 days chick embryo.
• Vaginal mucus agglutination test; this test seems to be helpful in the diagnosis of the disease. Antibodies can/ be demonstrated between 30 to 70 days after initial infection.
• Indirect haemagglutination test; two test have been employed. In one of the tests normal sheep erythrocyte is sensitive with heat stable fraction of c. fetus as antigen. The test utilizes tanic acid treated sheep erythrocytes sensitized with phenol soluble fraction of c. fetus as antigen and is considered more sensitive than the former.
• F.A.T; Preputial flushing of the bull may be brought under F.A. test. For this prepucial cavity of bull is flushed with 4 ml of bacteriological broth and or saline solution and forwarded to laboratory for F.A.T. Based on the study remarked that fluorescent antibody technique is preferred method for detecting campylobacteriosis.    

TREATMENT

Usually, treatment is not required, except electrolyte replacement and rehydration. Antimicrobial treatment is recommended in invasive cases (when bacteria invade the intestinal mucosa cells and damage the tissues) or to eliminate the carrier state (the condition of people who harbor Campylobacter in their bodies and keep shedding the bacteria while remaining asymptomatic).

PREVENTION METHODS

There are a number of strategies that can be used to prevent disease. They include:

• Prevention is based on control measures at all stages of the food chain, from agricultural production on a farm, to processing, manufacturing and preparation of foods both commercially and domestically.
• Bactericidal treatment, such as heating (for example cooking or pasteurization) or irradiation, is the only effective method of eliminating Campylobacter from contaminated foods.
• In countries without adequate sewage disposal systems, feces and articles soiled with feces may need to disinfect before disposal.
• Prevention methods against infection in domestic kitchens are similar to those used against other foodborne bacterial disease.
• Good hygienic slaughtering practices reduce the contamination of carcasses by feces, but will not guarantee the absence of Campylobacter from meat and meat product. Training in hygienic food handling for abattoir workers and raw meat producers is essential to keep contamination to a minimum.
• Measures to reduce the prevalence of Campylobacter in poultry include enhanced biosecurity to avoid transmission of Campylobacter from the environment to the flock of birds on the farm. This control option is feasible only where birds are kept in closed housing conditions.

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REFERENCE:

• Sahin O, et al. Annu Rev Anim Biosci. 2017
• www.who.int
• R. D. Sharma, Mahesh Kumar;