Listeriosis: Cattle Infectious Disease PDF

1 Dept. of medicine and infectious dis., Fac. Of Vet. Med., Univ. of Sadat City  University of Sadat City Faculty of Veterinary Medicine Dept. of medicine and infectious dis., Fac. Of Vet. Med., Univ. of Sadat City 2 ‫قالوا سبحانك ال علم ل...

1 Dept. of medicine and infectious dis., Fac. Of Vet. Med., Univ. of Sadat City  University of Sadat City Faculty of Veterinary Medicine Dept. of medicine and infectious dis., Fac. Of Vet. Med., Univ. of Sadat City 2 ‫قالوا سبحانك ال علم لنا إال ما علمتنا‬ ‫انك أنت العليم الحكيم‬ ‫صدق هللا العظيم‬ ‫سورة البقرة‪ -‬اآلية ‪32‬‬ ‫‪3‬‬ ‫‪Dept. of medicine and infectious dis., Fac. Of Vet. Med., Univ. of Sadat City‬‬ Cattle Infectious diseases contact information: Prof. Dr. Akram Ahmed Salama [email protected] 01008081474 4  Listeriosis Definition : Listeriosis is an infections disease caused by listeria monocytogenes. The infection is characterized by encephalitis , myelitis or kerato- conjunctivitis Etiology : 1)L. monocytogenes Gram + ve bacillus 2)Widespread in nature survive and grow in a wide variety of environment 3) Optimal growth temperature 30 – 37 C but it can grow at – 0.4 C- 45 C 4) It can grow at pH 4.5 – 9.6 5) It can survive in fecal material for several years  Etiology : 6) On the basis of somatic and flagellar antigens , there are 13 serovars 7) 4 6 , 1\ 2 a and 3 are most commonly isolated from disease problems in animals 8) Virulent strains produce a hemolysin , listeriolysin O , which is believed to be a major virulence factor 9)Virulence strains can be identified by their ability to multiply in : a) macrophages and monocytes b) The organism is susceptible to common disinfectants.  Epidemiology : I. Occurrence : 1) Clinical disease in animals occurs mainly in the northern and southern latidudes and is much less common in tropical and subtropical than in temperate climates 2) Listeriosis is primarily a disease of raminants , particalarly sheep , although occasional disease occurs in horses and pigs. 3) The disease occur in all sheep over 4 months age with high case fatality.  II.Transmission : 1) L. monocytogenes can be isolated from the feces and nasal secretions of healthy animals. 2) With septicemic disease and abortion the organism is transmitted by ingestion of contaminated material 3) Contamination of teats , ingestion of milk containing the organism , navel and congenital infection. 4) The encephalitic form results from infection of the terminals of the trigeminal nerve due to abrasion of the buccal mucosa from feed or from infection of tooth cavities  Risk factors I. I.Factors lowering animal resistance 1) Poor nutritional state 2) Sudden change of weather to very cold and wet 3) Stress of late pregnancy and parturition 4) Long period of flooding with resulting poor access to pasture 5) Overcowding and unsanitary conditions  Risk factors II. II.Factors increase infection pressure of the organism 1) Massive multiplication of L. monocytogenes in the feed or environment 2) Feeding grass or corn silage ( common inhabitant in the silage ) 3)Effectively preserved silage characterized by: *Anaerobic storage *High density High concentration of organic acids *pH below 4.5 depend on dry matter content (L.monocytogenes can not grow on it  Clinical Finding I.: I. Listerial encephalitis: The most common form of the disease. 1) Early stage, separation from the flock, depression, desire to escape from the flock due to incoordination, they run and fall easily. 2) Sings of cranial nerve dysfunction as : - incoordination – herd deviation – walking in a circles – facial paralysis ( drooping of ears , paralysis of lips ) 3) Keratitis , corneal ulceration , panophthalmitis with pus evident in the anterior chamber of the eye.  Clinical Finding: II. 4) Dropped jaw , drooling saliva with food hanging from its mouth. 5) Fever 40 – 42 c* 6) In adult cattle the course of the disease is usually 1 – 2 weeks but in sheep and calves the disease is more acute , death occuring 2 – 4 days. 7) In goats the onset of the disease is very sudden and the course is short with death occuring 2 – 3 days.  Clinical Finding: III. II. Listerial abortion : 1) Outbreaks of abortion are recorded in cattle but occur more commonly in sheep and goats 2) In cattle : a) Abortion or stolbirth in last third of pregnancy b) Retention of placenta with clinical disease & fever c) Common after silage feeding. 3) In sheep and goats : a) Abortions occurs from the 12 week of pregnancy b) Retention of placenta c) Blood – stained vaginal discharge for several days d) Death of ewes due to septicaemia if the fetus is retainedIn 4) In all species the incidence of abortion is low but may reach 15 %  Clinical Finding: IV. III. Septicemic Listeriosis : 1) Not common in adult animals but occurs in lambs and calves. 2) Depression , weakness , emaciation , pyrexia and diarrhae 3) Corneal opacity with dyspnea IV Mastitis 1) Infection in the udder involves a single quarter , is chronic and poorly responsire to treatment 2) High somatic cell count in milk from the affected quarter the milk appears normal  Clinical Finding: V. V. Spinal myelitis : 1) Most commonly there is initial knuckling of the hind limbs progressing to hind limbs weakness and paralysis 2) In some cases paresis and paralysis of the front limbs 3) There is no evidence of cranial nerve involvement Bovine listeriosis (circling disease) often occurs with brain abscess resulting in blindness and neurological dysfunction. Listeriosis: Sheep walk in a circle of a small diameter  Necropsy findings : 1) Cerebrospinal flnid may be cloudy with congestion of cerebral vessels. 2) Histological examinations reveals micro abscess in the brainstem 3) Visceral lesions occurs as multiple foci of necrosis in the liver spleen , endocardium and myocardium especially in the septicaemic from. 4) In aborted lambs & calves : a) Small yellow foci of necrosis in the liver b)Small abomasal erosions c) Yellow orange – meconium d) Aborted fetuses are edematous , rarely mummified and autolyzed e) Placentitis and endometritis in aborted mothers.  Diagnosis I.: 1) Clinical diagnosis 1- Listerial meningio encephalitis should be differentiated from other diseases causing nervous manifestations in cattle and sheep as Rabies ,Tetanus , BSE and other non – infections causes. 2- Listerial abortion should be differentiated from other diseases causing abortion in cattle, sheep and goats 3-Acute septicemia are due to many causes but association with abortion and stilbirths may suggest the possible presence of listeriosis  Diagnosis II.: II. Serological tests : 1- Agglutination and complement fixation tests have been used but lack the predective value required for diagnostic use. 2- Titers highly than 1 : 200 are usually associated with listerial infection III. Isolation of L. monocytogenes : Isolation of the organism from the feces , urine , milk , aborted fetuses and vaginal secreations Listeriosis: meningitios secondary to vasculitis Listeriosis: microglia nodules and edema of the brain tissue Brain abcess: diffrential diagnosis of listeriosis  Treatment : L. monocytogenes is resistant to may drugs 1) Intravenous injection of chlortetracycline 10 mg \ kg [ 15- 20 mg \kg ] body weight per day for 5 days 2) Penicillin at a dose rate of 4400 I. U \ kg body weight given intramuscularly for 10- 14 days. 3) In lambs , dehydration , acid – base imbalance and electrolyte disturbances must also be corrected  Control : 1) Reduce the amount of silage in feed and supplement with low level of tetracycline 2) Change in diet to contain heavy feeding of silage should be made slowly 3) Attempts to produce a satisfactory vaccine has been unsucceseful · Alive attenuated vaccine has been used in cattle in Norway for several years · Commercial killed vaccines are available for the control of the disease.