clamydia lecture

Chlamydial abortion

Enzootic abortion of ewes (EAE), Ovine enzootic abortion,

Kebbing

Disease of sheep characterized by late term abortion and/or still

birth.

Etiology• Chlamydiophila abortus (Chlamydia

psittici serotype 1) • Gram negative (2 phases).

Extracellular infective phase; Elementary body (EB), Intracellular phase; Reticulate body (RB)

• formalin & heat susceptible (die in 4-10 days)

EpidemiologySusceptibility: sheep (goats, cattle, swine,

humans).

Transmission: ingestion.

Source: aborted uterine discharge and placentas.

Epidemiology

Usually start in first season as sporadic abortion which become storm of abortion in the second season (30% abortion).

Usually in areas with high density of sheep.

Clinical Signs Abortion in the last 2-3 weeks of

pregnancy of Well-developed lambs. Some of them are premature or full-term still birth.

Live weak lambs die. Few give good lambs.

Clinical SignsAnimals does not abort more than once. Rams could be infected with orchitis and

secrete in semen (no evidence for transmission to ewes).

Pathology Necrosis of cotyledons and rough thickening of

intercotyledonary tissues.

Diagnosis

• Clinical + History• Confirmation

– Smears of placenta ( stained by modified zeihl-neelsen or Giemsa)red bodies against blue background.

– ELISA, CFT antibody titre.– Isolation on Yolk sac of chick embryos.

Control and prevention

Isolation of aborted animals (either culled or kept).

removal of beddings and discharges.

long acting oxytetracycline (20mg/kg) every2 weeks.

Control and prevention

Vaccination using inactivated adjuvant vaccine 4 weeks before mating then revaccinate every 3 years.

New animals should come from clean flocks.

Brucellosis

Contagious disease of sheep and goats characterized by storm of

abortion at last third of pregnancy.

Etiology• B.melitensis (biovar 3 in Egypt)• B. abortus• B. ovis (ram epididymitis, veneral)

Epidemiology

Geographic distribution.

Susceptibility: goats and sheep> cattle> humans.

Transmission: contagious: ingestion, inhalation, conjunctival, nasopharyngeal, skin breaks mucous membranes in the male and female reproductive tract and udder .

Epidemiology

Source: aborted animals uterine discharge and placentas, urine, milk, faeces. Intrauterine.

Latent infection.

Chronic carriers especially in goats which secrete intermittently the Brucella throughout its life.

Epidemiology

A high proportion of infected animals especially sheep eliminate the infection completely (self-limiting) and exhibit long life immunity against reinfection.

Clinical Signs• Abortion in the last 2 months of

pregnancy ( storm in first season up to 70%)

• Retained placenta, interstitial mastitis, reduction of milk production, orchitis of males and infertility of both sexes, hygroma of the joint and arthritis

Diagnosis

• Signs .• Bacteriological methods• Serological tests ( field fast tests

with high sensitivity RBPT, BABA) ( confirmatory tests CFT, ELISA).

• Allergic tests ( Brucellin test herd test).

Control

Isolation of aborted animals and burning of all foetal discharges.

Isolation of newly born animals and feed them from other negative dams and test them at 3-6 months , if they are positive must culled.

Disinfect the farm with carbolic acid. Clean farms or countries should test

all animals before introduction.

Control

• Test and slaughter policy in low endemic farms or countries ( < 2% prevalence). And the farm become clean after 3 negative successive tests 2 months apart.

• Avoid uncontrolled animal movement and animal trade.

• Vaccination of highly infected farms or countries ( > 10% prevalence).

Control

Rev 1 vaccine full dose (3 month sc. Animal must be

tested before breeding). long period of immunity 4.5 years. Zoonotic, if given to adults

serocoversion and abortion. So if given to adults , should be reduced

dose and conjunctival but still abortifacient.

Control

H38 vaccine Inactivated Gives protection for 15 month. Very long antibody titre. Sever reaction at injection site. High production cost

Braxy

acute disease of sheep characterized by inflammation of abomasal wall, toxemia and high

mortality rate. .

Etiology• Clostridium septicum ( Alpha, Beta

toxins), it is naturally inhabitant of soil and ovine GIT.

• Pathogenesis• Frosted food abomasitis

multiplication of Cl. septicum in the mucosa and sub mucosa of the abomasum exotoxin haemorrhagic inflammation in the wall of the abomasum and toxemia.

Epidemiology

mainly good strong sheep 6-18 month.

Transmission: ingestion

Source: soil and faeces of infected animals

cold weather. case fatality up to 50%.

Clinical Signs Sudden death Abdominal pain, fever, anorexia,

isolation , recumbency and comma.• Pathology Rapid autolysis of carcasses haemorrhagic abomasitis with ulcers. sero-anguious fluid in abdominal cavity.

• DiagnosisHistory Clinical signs

PM lesions Isolation and identification • Direct smear large numbers of Gram

positive rods. Fluorescent antibody tech.• Culture on blood agar.

• Treatment- Of less value (penicillin)• Control and prevention. Animals should have a dry matter

feeding before let out to frosted pasture. Vaccination: formalized whole culture

vaccine in 2 doses 3-6 weeks apart in early winter.