Trypanosoma gambiense and Trypanosoma rhodesience

Introduction

• gambiense causes disease called sleeping sickness in man. Pigs, cattle and dogs may also get infected. Transmission is through Glossinapalpalis.
• rhodesience causes Rhodensiense disease or east African sleeping sickness in man and transmitted by Glossina morsitans.

T. brucei equiperdum

Introduction

• Indistinguishable from evansi but are slightly smaller and have less mortality.
• Causes general disease of horse called ‘Uourine’ (Arabic word meaning unclean (dirty) or equine syphilis or breeding paralysis.
• Transmitted through goitus. In rare cases, transmission is through biting flies and by infective discharges contaminating mucous membrane.
• Incubation period : 2-12 weeks.
• Clinical case usually progresses through three phases

1^st phase (stage of edema)

• Starts with mucoid, vaginal or urethral discharge, degree of nymphomanta and mild fever with oedema of genitalia.
• Prepuce and scrotum are swollen in case of stallion. May extend under belly.
• In mare, vaginal mucosa is hyperaemic and ulcers may be present.
• Deep pigmentation of circumscribed areas of Vulva and penis. Last 4-6 weeks.
• In severe case, there is frequent micturition and even abortion in pregnant mares. Appetite is not affected.

2^nd phase (Urticarial phase)

• Appears after 4-6 weeks of first phase.
• Oval or spherical plaques of about 3 cm or more in diameter appear on skin on sides of body, especially in flank region. They are pathognomonic finding of disease and classically referred to as ‘ dollar spots’ since they appear as if a silver dollar or a rupee coin has been inserted under skin.
• Anemia and animal get emaciated.
• Inguinal lymph glands are enlarged
• Intermittent fever is present but the appetite remains normal.

3^rd phase (Phase of paralysis)

• Incoordination and unilateral paralysis affecting hind limbs, lips, nostrils and ears.
• Complete paralysis and recumbency in later stage, followed by death.

Diagnosis

• Based on pathognomonic symptoms
• Defection of organism in smears from mucous membrane of genitalia and urticarial swellings.
• Animal inoculation: Inoculation of blood into laboratory animals, in case of negative results in smears for parasite.

Treatment and control

• Antrycide and suramin is drug of choice
• For control, ‘test and slaughter’ policy is recommended. In cases, where it is not feasible, affected animals may be castrated to avoid spread of infection.