Short Notes on Nematology

1.Sweating Blood:

Parafilaria multipapillosa of horse are found in the subcutaneous tissue.   which affects horses causing hemorrhagic subcutaneous nodules in the head and upper forelimbs. Clinically , the condition is characterized by matting of the hair due to blood and tissue fluid exudates from ruptured nodules.  This lession is seen usually in hot weather particularly in summer season. So it is called Sweating blood . It is also referred to as "Summer bleeding".

Although the condition is disappear in cold weather and particularly reappear during wormer months for up to 4 years of individual animals.

2.Husk Diseases:

Dictyocaulus viviparus is the most common lungworm of cattle; the infection is also known as husk or parasitic bronchitis.Grazing cattle ingest the infective larvae from the pasture and within four weeks of ingesting these larvae, the cow or calf can be shedding millions of fresh larvae onto the pasture.Husk diseases are mainly seen in the late summer or autumn. Signs in cattle range from a mild cough and slightly increased breathing rate to severe and persistent coughing and difficulty breathing. In young stock the main effect is a depression in growth rates, leading to a longer finishing period or time to first service. In older cattle the disease can depress milk yields, compromise fertility and even kill animals.
Effective control strategies include vaccination, effective use of wormers and strategic grazing management.

3.Cutaneous larva migrans

Cutaneous larva migrans (abbreviated by CLM) is a skin disease in humans, caused by the larvae of various nematode  of the Family: Ancylostomatidae. The infection causes a red, intensely pruritic (itchy) eruption. The most common species are Ancylostoma braziliense,  Ancylostoma duodenale . 

Hookworm eggs are shed in infected dog  feces to the ground, where they then develop over a period of 1–2 weeks into the infectious larval form. The filariform larvae can burrow through intact skin that comes into contact with soil or sand that is contaminated with feces. Although they are able to infect the deeper tissues of animals through to the lungs and then the intestinal tract. Humans are incidental hosts and the larvae are only able to penetrate the upper dermis of the skin and thus create the typical wormlike burrows visible underneath the skin. These parasites apparently lack the collagenase enzymes required to penetrate through the basement membrane deeper into the skin.

4.French Heartworm:

Angiostrongylus vasorum, also known as French heartworm, is a species of parasitic nematode in the family Metastrongylidae. It causes the disease canine angiostrongylosis in dogs. It is not zoonotic, that is, it cannot be communicated to humans.

These nematode worms are small and pinkish in color . The length is 14.0–20.5 mm . The width is 0.170-0.306 mm .  Females have a barbers pole appearance.

Life Cycle:

The life cycle begins when L3 larvae are ingested by a definitive host, primarily the fox or dog. This can be through eating mollusc (intermediate hosts), frogs (paraentenic hosts), or from food infected with slime from the slugs or snails. The L3 larvae migrate to the mesenteric lymph nodes and moult to L4, and L5. The L5 larvae migrate through the portal circulation and through the liver and the adults end up at the pulmonary artery or right side of the heart.

The adults then mate and produce eggs. The eggs move to the alveolar capillaries via the circulation and hatch to L1 larvae. The L1 larvae burrow though the alveolar and are then coughed up and swallowed. L1 larvae are therefore passed in the faeces of infected cannids.

The L1 larvae infect intermediate hosts (primarily slugs and snails) by penetrating the foot of the mollusc and develop to L3 within.

Adult worms can live for 2 years. The pre-patent period is 6–10 weeks.

5. Verminous aneurysm and verminous colic:

Verminous aneurysm is an aneurysm of equines caused by the nematode named, Strongylus vulgaris,Usally in the anterior mesenteric artery. Called also verminous mesenteric arteritis.The clinical manifestations, diagnosis and differential diagnosis of "verminous aneurysm" formation at the root of the cranial mesenteric artery and coeliac artery resulting from Strongylus vulgaris larvae migration.  

An aneurysm is a vascular dilation caused by weakening of the tunica media of blood vessels. The weakness might be primary or caused by degenerative or inflammatory changes progressing from an intimal lesion. False aneurysms (pseudoaneurysms) are caused by damage to all three layers of the arterial wall and result in extravascular accumulation of blood. Disruption of the endothelium associated with a true aneurysm can cause formation of a thrombus with subsequent embolization; thus, aneurysms, thrombi, and emboli may be recognized simultaneously. Aneurysms are rare in domestic animal species, although they have been reported in dogs, cats, horses, primates, and turkeys.

Kazi Abdus Sobur

DVM (Expected-2018)

Bangladesh.

kazisobur@gmail.com