How To Know Larva Migrans Infections
Visceral Larva Migrans
The term “Visceral larva migrans” is used to denote the manifestations produced by larvae of non-human ascarids when they migrate through human tissues. Most often, the ascarids of dogs and cats- Toxocara Canis and Toxocara Catis- are the offenders. Though larvae migrate in human tissues for variable periods, the adults do not develop in man. The larvae migrate in the pulmonary and visceral capillaries evoking a granulomatous reaction in various organs. They die and the lifecycle is terminated at this stage in non-canine hosts. However, in female dogs, the larvae pass transplacentally into the fetus in utero and the adults develop in the puppies. They eliminate the eggs in feces in the first few months. Children between the age of one and four, who are in close contact with puppies are at high risk of infection.
The infection is acquired by ingesting the ova. The larvae are liberated in the jejunum and they migrate into tissues like liver, lung, heart, brain, ocular structures, kidneys and muscles.
Clinical Features: In the majority of cases, the condition is asymptomatic. In a few, symptoms such as fever, cough, wheeze, abdominal pain and pallor develop. The central nervous system may be involved leading to headache, visual disturbances, strabismus and convulsions. The CSF pleocytosis with eosinophil predominance may occur. Nodular eruptions and urticaria may develop as skin manifestations. Eye lesions include exudative endophthalmitis and retinal granuloma. These may impair vision considerably. Some children develop hepatomegaly.
Visceral larva migrans is self-limiting, since the encysted larvae die out after varying periods. Involvement of liver, lung, brain or eyes calls for treatment. Anthelminthic drugs should be used with caution since allergic reactions which could damage vital organs further may result from rapid destruction of the larvae.
Diethyl carbamazine and thiabendazole are useful against visceral larva migrans; the latter is preferable because of its anti-inflammatory property. Thiabendazole is given in a dose of 50 mg/Kg body weight in divided doses daily for 2 to 3 days. Steroids are given in severe pulmonary involvement, since ocular lesions like choroidoretinitis may appear and progress long after specific treatment, such patients should be followed up for several years after treatment.
Larva migrans can be prevented by proper de-worming of newborn pets and avoiding contamination of children’s playground with the excreta of these animals.
Diagnosing Cutaneous Larva Migrans
Cutaneous Larva Migrans
The larvae of Ancylostoma braziliense and A. caninum (dog’s and cat’s hookworms) and strongyloides stercoralis cause creeping eruption. The larvae which are present in soil penetrate the intact skin and enter the tissues. In the subcutaneous tissues, they cause multiple, intensely pruritic serpiginous tracts which progress forwards 2 to 3 cm at a time. At the anterior end of the eruption, the larva is present and a bleb may form. Since the larvae ultimately die, the lesions are self-limiting. The eruptions due to strongyloides tend to persist for several years, if left untreated.
Treatment: The condition responds to thiabenzadole in a total dialy dose of 50 mg/Kg body weight given orally in divided doses for 2 to 3 days. Antihistamines help to suppress the pruritus.
© 2014 Funom Theophilus Makama