2. Introduction
• Synonym: Gall sickness
• Anaplasmosis is an infectious vector borne disease of
ruminants.
• Caused by obligate intra-erythrocytic rickettsia organism of
the genus Anaplasma. (Ristic and Kreier 1984)
• Characterized clinically by high fever, inappetence ,decrease
milk yield, progressive anaemia, icterus(jaundice).
3. Etiology
• Anaplasma marginale : Cattle and wild ruminants.
• A centrale is closely related to A. marginale and cause mild
anaplasmosis in cattle.
• A. ovis : Sheep, goat and deer.
4. Epidemiology
Distribution:
• Occurs in tropical and subtropical regions worldwide
including South and Central America, the USA, southern
Europe, Africa, Asia, and Australia.
Host range:
• Cattle are susceptible to A. marginale and A. centrale.
• Sheep susceptible to A. ovis.
Source of infection:
• The source of infection is always the blood of an infected
animal.
• Recovered carrier animals are the source of infection.
5. Risk factors:
• Animals of any breed and sex can be affected.
• Sheep and goat, as well as certain wild ruminants, can be
laterally infected with A. marginale.
6. Risk factors(contd)
Age at infection:
• Young calves up to 6 months are usually susceptable to
infection and mostly subclinical.
• Calves aged between 9 to 12 months develop only a mild form
of the disease.
• Cattle aged between 1 to 2 years may develop acute but rarely
fatal disease symptoms.
• Acute and occasionally fatal infections occur in cattle more
than 3 years of age.
7. Risk factors(contd)
Nutritional status
• Shortage of feed and concurrent diseases may result in the
development of acute anaplasmosis.
Season:
• Seasonal occurrence of disease occurs in association with
seasonal occurrence of the insect vectors.
• Winter outbreaks are likely associated with iatrogenic
transmission.
10. Pathogenesis
• Anaplasma are obligate intra-erythrocytic parasites. That infect
mature erythrocytes by endocytosis.
• Characterized by progressive anemia due to extravascular
destruction of infected and uninfected erythrocytes
• The number of infected erythrocytes become double in every
24-48 hours.
11. Clinical findings:
• Seen as per-acute, acute and chronic form.
• lose condition rapidly.
• Milk production falls
• High fever
• Severe dyspnoea
• Urine may be brown in color.
• Anemia (Mucous membranes appear pale and then yellow)
• Pregnant cows may abort
• Icterus.
12. Fig: Pale and icteric mucous
membrane
Fig: Emaciation in chronic form
13. Necropsy findings:
• Carcasses are generally markedly anemic and jaundiced.
• Blood is thin and watery.
• Splenomegaly due to involvement of the reticuoendothlial
system.
• Hepatomegaly
• The gallbladder appears enlarged and is distended with thick
yellow-green bile.
• Epicardial and pericardial petechiae and ecyhmoses are often
present.
• The lungs are usually pale and edematous.
14. Diagnosis
Tentative diagnosis:
• Clinical findings (fever, anemia, emaciation, icterus, drop in
milk yield, abortion).
History include:
• Blood sucking arthropods.
Erythrocyte count, packed cell volume and haemoglobin
values are all severely depressed.
15. Definitive diagnosis:
• It depends on demonstration of Anaplasma bodies in
erythrocytes of affected animals.
• In Giemsa stained peripheral blood smear organism appear as
homogenous, dense, deep purple in color.
• The Serological test is Fluorescent antibody technique (FAT),
CFT, Tube agglutination test, ELISA test.
17. Differential diagnosis:
Anaplasmosis and Babesiosis
• Absence of haemoglobinuria in an anaemic or icterus animals.
Anaplasmosis and Trypanosomiasis:
• Trypanosomiasis usually occurs within well- defined Tsetse
infected areas .
Anaplasmosis and Theileriosis:
• Theileriosis affects cattle distinguished by enlarged lymph.
18. Control and prevention
• Control or elimination of the arthropod vectors may be a
viable control strategy.
• Elimination of carrier animal from the flocks.
• Chemoprophylaxis: Oxytetracycline used for throughout the
vector season.
• Vaccination (both live & killed vaccine is used).
