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A unique case of a larva migrans lentis in a 33-year-old female is presented. The intraocular larval (obviously Toxocara) affection was characterized in the first phase by the development of a peripheral chorioretinal granuloma and in the second phase by the finding of larva migrans in the lens. The lively larva appeared several times in the pupillary area under the anterior and posterior lens capsule and survived an intensive treatment by Mintezol.
Two patients had ocular manifestations of infestation with visceral larva migrans. In neither case did the eye involvement improve despite thiabendazole, local and systemic steroids, and cryotherapy. The lack of ocular response to treatment may be assumed to be because of organisms were already dead. Thiabendazole therapy is probably worth trying for early ophthalmic involvement with visceral larva migrans if the organism is still alive. In most cases the diagnosis of visceral larva migrans can be made with the help of the ELISA serum antigen determination so that enucleation of the eye will not be necessary for diagnostic purposes.
For both visceral larva migrans and alveolar hydatid diseases, it is the feces of companion animals that are the primary source of human infection. Clearly, whatever is done to reduce this form of environmental contamination and the prevalence of the parasites' infective stages will help to protect the health of the human population in the United States and Canada, particularly the children. Very important are appropriate anthelmintic treatment programs, especially for T. canis, and proper control of close associations between pets and people. Probably the known incidence of visceral larva migrans in humans and the range of its known pathogenicity will increase as better diagnostic methods become available. In addition, other animal helminths, for instance Toxocara cati and Toxascaris leonina, may become more substantially documented as causes of human visceral larva migrans. Until more is known of the geographical distribution and prevalence of Echinococcus multilocularis among animals in North America, it will be difficult to assess accurately the future significance of alveolar hydatid disease in the continent's human population. Another important advance would be the development of anthelmintics that are effective for somatic second stage larvae of T. canis, and others effective for adult or larval Echinococcus species. Meanwhile it is a most important responsibility of the veterinary profession to educate its clients thoroughly concerning these dangerous helminths.
Four serologic techniques for the diagnosis of visceral larva migrans caused by Toxocara canis, namely indirect hemagglutination (IHA), bentonite flocculation (BF), enzyme-linked immunosorbent assay (ELISA), and double diffusion in agar (Ouchterlony), were evaluated using sera sent to the Center for Disease Control from patients with a presumptive diagnosis of visceral larva migrans (VLM). Patients having 5-6 of the clinical or laboratory criteria for VLM were designated as cases while those with 0-2 criteria served as controls. The sensitivity of the ELISA was 78.3% compared to 18.2%, 25.8% and 65.2% for the IHA, BF, and Ouchterlony, respectively; the sepcificity of all four tests was greater than 92%. The predivtive value of positive test was greater than 85% for all tests except the IHA, while the predictive value of a negative test was greater than 85% only for the ELISA. The results of a ELISA were reproducible in different laboratories. Based on these findings, the ELISA using a larval antigen appears to be the serodiagnostic method of choice for VLM.
Seven of 10 patients with visceral larva migrans (VLM) had serum precipitating antibodies specific for larval antigens of Toxocara canis as determined by double diffusion in agar. Such antibodies were absent in 114 normal adults and 25 patients with collagen disease. Precipitation of ascarid components by C-reactive protein resulted in false-positive reactions, but this precipitation was readily prevented by appropriate absorption of sera before testing. A more sensitive assay, the enzyme-linked immunosorbent assay, revealed high titers of antibodies to larvae of Toxocara in all patients with VLM; the log2 titer ranged from 9 to 14. Five of eight household relatives of these patients and four children who had had VLM two to four years before testing had titers of 6-12. Of the 114 normal adults, 105 had titers of 0-2; nine had titers of 3-8. Of the 25 patients with collagen disease, 23 had titers of 0, and two had titers of 4 and 6, respectively. Additional studies of those patients indicated that infection with Toxocara can be distinguished serologically from ascariasis, filariasis, and trichinellosis.
The clinical records of patients with visceral larva migrans confirmed through laparoscopy and other tests are reviewed. This review was prompted by the admittance of two patients with this affection in the last years. Medical literature was reviewed, and conclusions are made.
Visceral larva migrans, Entamoeba coli, evidence of latent toxoplasmosis and a history of plumbism were found in an emotionally disturbed, retarded child. Patients with pica should be screened for parasitism and other diseases transmitted orally.
The microprecipitation test on second generation larvae of Toxocara canis has proved to be highly specific for the diagnosis of human larva migrans visceralis infection caused by Toxocara species. Out of a total of 2864 samples examined from 1969 to 1976, 248 were found to be positive. Besides a very frequently occurring eosinophilia eye affections, lung changes and involvement of the CNS are prominent clinical symptoms. The investigations show that larva migrans visceralis infections also occur in West Germany, even if more rarely than in other countries. The diagnosis is only seldom made because of the lack of uniformity of the clinical symptomatology.
A husband and wife contracted larva migrans while vacationing on the Gulf of Mexico. Subsequently, migratory pulmonary infiltrates and peripheral eosinophilia (Loeffler's syndrome) developed in both patients. Their cutaneous lesions were treated with topical thiabendazole and resolved within two weeks. The pulmonary complication was treated symptomatically and resolved during the next eight weeks.
Toxocara larval excretions and secretions collected from in vitro culture were used as antigen in passive haemagglutination and soluble antigen fluorescent antibody tests for the diagnosis of visceral larva migrans in experimental animals and man. Antibody to toxocaral secretions was detected in rabbits within 13 days of light Toxocara infection (ten larvae per kg) and within four days of heavy infection (10(4) larvae). Antibody was not detected following infection with 10(4) Ascaris suum larvae. In human sera, antibody was detected at low titre in 1% of 100 healthy adults and in 2% of 50 children. High titres were observed in one third of 170 patients with suspected visceral larva migrans and in 23 of 27 such patients presenting with an eosinophilia greater than 20%. In 25 patients with ocular lesions of an undiagnosed nature, four showed significant levels of anti-Toxocara antibody.
Visceral larva migrans is a disease in which the larvae of animal parasites invade human tissues but do not complete their life cycles. The most frequent cause of this illness in children is the dog roundworm, Toxocara canis. A review of the literature, as well as our clinical experience, indicates that there are two forms of clinical expression: one, visceral, and the other, ocular. In general the clinical and laboratory abnormalities (hepatomegaly, recurrent pneumonia, eosinophilia, and hyperglobulinemia) usually associated with visceral disease are absent in children with ocular abnormalities. Conversely, there is a general lack of eye complications in patients with systemic disease. Reasons for these variations in clinical expression are unknown, but immune responses of the host and the antigenic composition of the parasite may be contributing factors.
A 20-year-old female patient who presented papylo-erythematous lesions with intense pruritus and arciform sinuous lesions in the back and gluteal regions during a stay at a beach is presented. A cutaneous larva migrans was diagnosed through biopsy. A brief bibliographic review of this parasitologic entity is made.
Extracts of nematodes have been used as skin test antigens in the diagnosis of nematode infections for many years. Ascaris lumbricoides and Toxocara canis are two nematodes commonly involved in human parasitism, the latter being associated with the clinical condition of Visceral Larva Migrans. In vitro and in vivo experiments reported in this paper confirm experimentally, as well as clinically, the existence of cross-reacting antigens between T. canis and Ascaris spp., and probably between T. canis and other nematodes. These cross-reactions compromise the usefulness of skin tests in the diagnosis of such parasitic infections.
Experiments in 3 weeks old albino mice with Toxocara canis and sublethal infection with JE virus established a marked synergestic effect in dually infected mice. The results are discussed to indicate the possible role of visceral larva migrans in creating exploxive outbreaks of "acute encephalopathy syndrome" in individuals having simultaneous infection with a virus (es) which, alone, might produce only mild illness. The nature of the possible mechanisms involved yet remains to be understood.
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