Monograph

Thu, 01/27/2011 - 15:10 — Anonyme

definition:

Babesiosis are diseases of parasitic origin transmitted by ticks.

They have a major economic impact due in particular to often high mortality and morbidity. They remain one of the main obstacles to the growth and improvement of cattle breeding in most regions of the world.

They appear on the OIE list.

Situation in America:

Babesiosis are distributed worldwide, but have a larger presence in tropical regions with an abundance of their vectors.

Despite strong seropositivity in numerous islands of the Lesser Antilles, none are epidemiologically stable, a stability affecting over 90% of seropositive cattle.

Susceptible species:

Cattle can be infested with Boophilus microplus, a tick that carries babesiosis. However, B. microplus has a relatively modest direct or indirect pathogenic influence on Creole cattle, the majority of Guadeloupean cattle.

Small ruminants are either not infested by this tick or not significantly so, meaning that there is a very low risk of these animals contracting the disease.

• B. bovis and B. bigemina : cattle, water buffalo (Bubalus bubalis) and African buffalo (Syncerus caffer), reports of disease in white-tailed deer (Odocoileus virginianus) in Mexico

• B. divergens : cattle and reindeer (Rangifer tarandus), Mongolian gerbils (Meriones unguiculatus); other peridomestic rodents are resistant to disease, Splenectomised humans and non-human primates are highly susceptible, Experimental infection with no clinical signs have been documented in splenectomised ungulates including mouflon (Ovis musimon), red deer

Etiological agent:

Babesiosis are caused by intraerythrocytic parasitic protozoa belonging to the Babesia genus; in Guadeloupe, Babesia bovis and B. bigemina are present.

They are transmitted by ticks of the Boophilus microplus species,the "creole tick" found across the Antilles and the South American continent.

Source Queenslang government

Methods of transmission

Transmission:

In cattle, the infected Boophilus microplus tick is responsible for transmitting the disease, although other species of tick may also be to blame.

The larva phase is the only stage involved in the transmission of Babesia bovis, whereas B.bigemina can be transmitted by pupae, females and males.

Symptoms:

Incubation period: 8 to 16 days after infected ticks begin feeding

Animals

Hyperthermia (41.5°C), apathy, anorexia, bristling hairs

Haemoglobinuria followed by the appearance of jaundice

Then constipation, tenesmus, dehydration, shivering, weakness, prostration

A cerebral form exists with the appearance of nervous signs: paddling, ataxia, aggressiveness, coma

Hypothermia precedes death, which is inevitable without treatment

Humans

Many people who are infected with Babesia microti feel fine and do not have any symptoms. Some people develop nonspecific flu-like symptoms, such as fever, chills, sweats, headache, body aches, loss of appetite, nausea, or fatigue.

Sometimes, Babesiosi can be severe.

Lesions

Macroscopic lesions:

• Lesions observed are those most often associated with an intravascular haemolytic condition
• Pale or icteric mucous membranes; blood may appear thin and watery
• Subcutaneous tissues, abdominal fat and omentum may appear icteric
• Swollen liver with an orange-brown or paler coloration; enlarged gall bladder containing thick,
granular bile
• Enlarged, dark, friable spleen
• Kidneys appear darker than normal with possible petechial haemorrhages
• Bladder may contain dark red or brown-colored urine
• Possible oedema of lungs
• Petechiae or ecchymoses on surface of heart and brain

Diagnostics

Clinical diagnosis:

Animals

Clinical manifestations of disease associated with BB are typical of a haemolytic anaemia disease process but vary according to agent (i.e. species of parasite) and host factors (i.e. age, immune status). BB is predominantly observed in adult cattle with B. bovis generally being more pathogenic than B. bigemina or B. divergens. Infected animals develop a life-long immunity against re-infection with the same species and some cross-protection is evident in B. bigemina-immune animals against subsequent B. bovis infections.

Babesia bovis
• High fever
• Ataxia and incoordination
• Anorexia
• Production of dark red or brown-colored urine
• Signs of general circulatory shock
• Sometimes nervous signs associated with sequestration of infected erythrocytes in cerebral capillaries
• In acute cases: maximum parasitaemia (percentage of infected erythrocytes) in circulating blood is often less than 1%

Babesia bigemina
• Fever
• Haemoglobinuria and anaemia
• Production of dark red or brown-colored urine
• Nervous signs minimal or non-existent as intravascular sequestration of infected erythrocytes does not occur
• Parasitaemia often exceeds 10% and may be as high as 30%

Babesia divergens
• Parasitaemia and clinical appearance are similar to B. bigemina infections

Humans

Difficult because no specific symptoms

Differential diagnosis:

• Anaplasmosis
• Trypanosomiasis
• Theileriosis
• Bacillary haemoglobinuria
• Leptospirosis
• Eperythrozoonosis
• Rapeseed poisoning
• Chronic copper poisoning

Laboratory diagnosis:

- Microscopique examination of blood (source Queenslang government) :

babesia bovis

- Detection of the pathogenic agent through Giesma staining of a peripheral blood smear or through PCR

Serological diagnosis:

Detection of antibodies through complement fixation, immunofluorescence or an ELISA test

Treatment:

Animals

Injection of Imidocarbe

Humans

Before considering treatment, the first step is to make sure the diagnosis is correct.

Effective treatments are available, and most people who are infected with Babesia microti respond well. People who do not have any symptoms or signs of babesiosis usually do not need to be treated.

However, do not treat it lightly because the consequences can be severe for those at risk

Prophylaxis:

Sanitary

Controlling the movements of cattle

Combating ticks: chemical measures, agronomic measures (reducing refuse, repellent plants), biological measures (predators: birds, ants), manual tick removal

Vaccines:

Attenuated live virus vaccine, although failure is common

Links:

CDC : babesiosis

OIE : terrestrial manual. chapter Bovine babesiosis