Eosinophilic meningitis beyond the Pacific Basin: the global dispersal of a peridomestic zoonosis caused by Angiostrongylus cantonensis, the nematode lungworm of rats.

The principal etiologic agent of human eosinophilic meningitis, Angiostrongylus cantonensis, was first detected in rats in Canton, China in 1933. The first human case was detected on Taiwan in 1944. Epidemic outbreaks were noted on Ponape (E. Caroline Is.) from 1944 to 1948. The disease may present as transient meningitis or a more severe disease involving the brain, spinal cord and nerve roots, with a characteristic eosinophilia of the peripheral blood and CSF. Since 1961 it has been known that human infections are usually acquired by purposeful or accidental ingestion of infective larvae in terrestrial mollusks, planaria and fresh-water crustacea. There is no effective specific treatment. The African land snail, Achatina fulica played an important role in the panpacific dispersal of the organism: it will be important in Africa in the future as well. Rats were, and will continue to be the principal agents of expansion of the parasite beyond the Indopacific area. During and just after WWII the parasite was introduced, and/or spread passively from South and Southeast Asia into the Western Pacific islands and eastward and southward through Micronesia, Melanesia, Australia and into Polynesia, sequestered in shipments of war material and facilitated by post-war commerce. In the 1950s numerous cases were identified for the first time on Sumatra, the Philippines, Taiwan, Saipan, New Caledonia, and as far east as Rarotonga and Tahiti. Then cases were detected in Vietnam, Thailand, Cambodia, Java, Sarawak, the New Hebrides, Guam and Hawaii during the 1960s. Subsequently in the Pacific Basin the disease has appeared on Okinawa, other Ryukyu islands, Honshu, Kyushu, New Britain, American Samoa and Western Samoa, Australia, Hong Kong, Bombay, India, Fiji and most recently in mainland China. The parasite in rats now occurs throughout the Indopacific Basin and littoral. Beyond the Indopacific region, the worm has been found in rodents in Madagascar (ca 1963), Cuba (1973), Egypt (1977), Puerto Rico (1984), New Orleans, Louisiana (1985) and Port Harcourt, Nigeria (1989). Human infections have now been detected in Cuba (1973), Réunion Island (1974) and Côte d'Ivoire (1979) and should be anticipated wherever infected rats of mollusks have been introduced. Caged primates became infected in zoos in Hong Kong (1978) and New Orleans and Nassau, Bahamas (1987). The use of mollusks and crustacea as famine foods, favored delicacies and medicines has resulted in numerous outbreaks and isolated infections. Economic and political instability, illicit trade, unsanitary peridomestic conditions and lack of health education promote the local occurrence and insidious global expansion of parasitic eosinophilic meningitis.(ABSTRACT TRUNCATED AT 400 WORDS)

Helminths as heirlooms and souvenirs: a review of new world paleoparasitology.

Evidence from studies on ancient human feces, intestinal contents and organs of preserved bodies has established that Enterobius vermicularis, Trichuris trichiura, Diphyllobothrium spp and probably Trichinella spiralis infected humans in the pre-Columbian New World. These species, and perhaps other common human helminths for which there is not yet convincing evidence, probably accompanied transberingeal immigrants and their dogs, and thus can be seen as heirloom parasites. Early humans on the American continents were affected by helminths of native animals such as Paragonimus and Cryptocotyle, and these have also been found in precontact human remains. Michael Kliks considers that the indigenous parasites infecting early Americans may be viewed as zoonotic souvenirs of some 50 millennia of migrations from Alaska to Patagonia. Among the most serious zoonoses would have been infection by cystic hydatid larvae of echinococcid tapeworms, the many enzootic filarial worms, and a variety of larval trematodes and nematodes.

Specific and cross-reacting antibodies in human responses to Onchocerca volvulus and Dracunculus medinensis infections.

Immunoelectroblotting and enzyme-linked immunosorbent assay were used to identify non-cross-reacting antigenic components of Dracunculus medinensis and the filarial worms Onchocerca volvulus, Loa loa, Wuchereria bancrofti, Brugia malayi, and Mansonella ozzardi. Parasite specific serodiagnostic ELISA systems for onchocerciasis and dracunculiasis were devised based on these findings. Phosphate buffered saline extracts of adult worms were passed through a column of monoclonal antibodies to phosphorylcholine (PC). Crude and PC-depleted extracts were reacted on ELISA plates with individual sera from subjects infected with a range of nematodes. Binding of total antibody (Ig) or IgG class antibody and IgG4 subclass antibody was revealed using goat antihuman-Ig-phosphatase conjugate, or appropriate mouse monoclonal antihuman-Ig-type-specific reagents, followed by goat antimouse-Ig-phosphatase conjugate. Specificity of ELISA was improved by restricting reaction to the host's IgG4 antibody subclass, and/or by removing PC determinants from crude antigens. In parallel immunoelectroblots, crude and PC-depleted extracts probed with pooled sera showed potentially useful diagnostic antigens, including a 12 kDa protein from D. medinensis and 14, 18, and 27 kDa proteins from O. volvulus. Two Onchocerca specific ELISA systems non-reactive with antibodies to D. medinensis were devised.

Angiostrongylus (Parastrongylus) eosinophilic meningitis.

Angiostrongylus (Parastrongylus) cantonensis is the commonest cause of eosinophilic meningitis in the world. Infective third-stage larvae develop in slugs and snails. Humans are infected primarily in the central nervous system after ingesting an infected intermediate host. Damage by motile worms, inflammatory responses to foreign bodies, and possible toxicity of worm substances work in concert to produce the pathologic and clinical picture of neurologic angiostrongyliasis. This disease manifests itself by headache, paresthesias, generalized weakness, and occasionally visual disturbances and extraocular muscular paralysis. Eosinophilic pleocytosis is the major laboratory finding. Although the diagnosis of neurologic angiostrongyliasis is usually made clinically, serologic methods such as ELISA (enzyme-linked immunosorbent assay) can be helpful. Occasionally, living larvae can be identified histologically in the CSF, eye, or other tissue. There is no specific treatment for this disease. Corticosteroids may be useful to relieve increased intracranial pressure. The role of anthelmintic drugs, such as thiabendazole and ivermectin, is not yet known. The prognosis of neurologic angiostrongyliasis is usually good; however, fatal and chronic cases do occur. Appropriate preparation of food, control of mollusks and planarians, and elimination of rodents are important measures in limiting the further spread of eosinophilic meningitis caused by A. cantonensis.

Studies on the traditional herbal anthelmintic Chenopodium ambrosioides L.: ethnopharmacological evaluation and clinical field trials.

Infusions and decoctions of the leaves, roots and inflorescences of the herbaceous shrub Chenopodium ambrosioides (American wormseed, goosefoot, epazote, paico) and related species indigenous to the New World have been used for centuries as dietary condiments and as traditional anthelmintics by native peoples for the treatment of intestinal worms. Commercial preparations of oil of chenopodium and its active constituent, ascaridol, obtained by steam distillation, have been and continue to be, used with considerable success in mass treatment campaigns. Ethnopharmacological studies in a community of Mayan subsistence farmers in Chiapas, Mexico, confirmed that decoctions containing up to 300 mg of dry plant material per kg body weight (MGKGW) were widely used and traditionally highly regarded in the treatment of ascariasis. However, therapeutic doses of up to 6000 MGKGW of powdered, dried plant had no significant anthelmintic effect on the adults of Necator, Trichuris of Ascaris. Gas-liquid chromatographic analyses of plant samples used consistently demonstrated the presence of ascaridol in the expected amounts. Possible origins of subjective belief in the efficacy of C. ambrosioides as used, may be related to the positive association of spontaneous, or peristalsis-induced passage of senescent worms immediately following a therapeutic episode. It is also possible that in the past varieties of the plant containing much more ascaridol were used. The results of these controlled field studies did not sustain widely held traditional beliefs, nor the value of therapeutic practices regarding this plant. It is, therefore, essential that all indigenous ethnomedical practices be objectively evaluated for efficacy and safety using appropriate protocols before being considered for adoptation or promotion in health care programs.(ABSTRACT TRUNCATED AT 250 WORDS)

The radioallergosorbent test (RAST) for the serological diagnosis of human anisakiasis.

The serum of patients with parasitologically confirmed and one patient with a clinically presumptive case of anisakiasis were tested by the radioallergosorbent test (RAST) and counter-electrophoresis (CEP) for IgE and IgG antibodies, respectively, using antigens prepared from larval (L3) stage Anisakis simplex and larval (L2) stage Toxocara canis. All sera were RAST-positive to the A. simplex antigen and RAST-negative to the T. canis antigen. All sera were CEP-negative to both antigens. The presence of a specific IgE antibody suggests that the RAST could serve as a useful technique for the serodiagnosis of anisakiasis in man.

Anisakis simplex and Terranova sp.: inhibition by larval excretory-secretory products of mitogen-induced rodent lymphoblast proliferation.

Excretory-secretory products were collected from supernatants of in vitro cultures of larval nematodes, Anisakis simplex (type I) and Terranova sp. (Hawaii type A). These materials were found to be more potent inhibitors of rodent lymphocyte blast transformation induced by concanavalin A and bacterial lipopolysaccaride than whole worm extracts of the same parasites. Inhibition of blast transformation was a result of cytostatic rather than toxic effects on proliferating lymphoid cells. The material(s) responsible for suppression are greater than 10,000 MW and are heat labile.

Anisakiasis in the western United States: four new case reports from California.

Four cases of transient anisakiasis in northern California acquired by ingestion of raw fish were reported to health authorities between May 1977 and June 1980. A single Phocanema decipiens-like 4th-stage (L4) larva was identified in each of two cases. A recently molted adult male P. decipiens with a fragment of attached L4 cuticle and prominent caudal papillae was recovered from a third person. The latter is the only human case known in which an anisakid worm developed to the adult stage was involved. Two Anisakis type I larvae were recovered in the fourth case, being the first parasitologically confirmed case of human infection with this worm described from the coterminous United States. Differential diagnosis was based on cuticular characteristics of larval types and stages as well as the presence of major internal organs. All infections were acquired during May and June. Subjects were 25-37 years old; three were female; two were of Japanese and one of Polynesian ancestry. Raw salmon or raw "red snapper" (probably Sebastes sp.) was the presumptive source of worms in one case each. Mild stomach pain and nausea were noted from the time of ingestion for up to 20 hours after the infective meal; worms were coughed up or found in the mouth up to 2 weeks thereafter. Five other incompletely documented California cases are discussed.

Histopathology induced by larval Terranova (Type HA) (Nematoda: anisakinae) in experimentally infected rats.

Terranova Type Hawaii A larvae, gavaged into the stomach of Wistar rats, demonstrated the ability to invade the stomach and intestinal tissues of the rat without penetrating the serosa. Lesions induced by these third-stage larvae were present in 25 of 37 (68%) inoculated rats. Larvae adhered to the mucosa of the stomach within 1 hr PI. Mucosal ulceration and acute, focal, hemorrhagic areas in the mucosa and submucosa were associated with most worm-penetrations. Reactions of inflammatory tissue occurred from 4 hr to 6 days PI and granulomas occurred by day 7 PI. Indurated craterlike lesions were noted 10 to 15 days PI. Resolving granulomas were present by day 30 PI. Chronic gastric ulcers were observed at day 30 PI.

Eosinophilic radiculomyeloencephalitis: an angiostrongyliasis outbreak in American Samoa related to ingestion of Achatina fulica snails.

For the first time in American Samoa an outbreak of eosinophilic radiculomyeloencephalitis was related to eating giant African snails (Achatina fulica) infected with Angiostrongylus cantonensis. Among 24 Korean fisherman sharing the same infective meal, 16 who ate raw or partially cooked snails became ill; five who ate boiled snails and three who ate none remained well. The ensuing illnesses began within 1-6 days, persisted up to 10 weeks, and were characterized by both peripheral blood and spinal fluid eosinophilia, severe pains, weakness and hyporeflexia of the legs, and dysfunction of the bladder and bowels. Eight patients also had transient hypertension and/or lethargy, and three became comatose. One man died 17 days after eating the infected snails, and maturing larvae of A. cantonensis were found in his spinal cord. Enzyme-linked immunosorbent assay titers for antigens of A. cantonensis were elevated to 1:64 or greater (mean 1:128) in all 10 patients tested. Treatment with thiabendazole had no appreciable effect on the clinical course of the illness.