Human serum sensitivities of Trypanozoon isolates from naturally infected hosts in the Luangwa Valley, Zambia

Of 235 Trypanozoon stocks isolated from naturally infected hosts in northeastern Zambia and tested by the Blood Incubation Infectivity Test (BIIT), 176 came from man, 37 from wild-caught tsetse, 11 from wild animals and 11 from domestic livestock. Of those from man, 2 gave unexpected, human-serum-sensitive (HSS) reactions on first testing; all 15 stocks from tsetse in the northern area (Kampumbu) were strongly serum-resistant (HSR) while 22 other infections, from tsetse in the southern area (Kakumbi), gave 1 equivocal, 11 positive and 10 negative test responses. HSR Trypanozoon infections were found in a bushbuck, a warthog, in a giraffe (for the first time) and in a "sentinel" goat, used to monitor SS transmission in a small SS endemic village.

Leishmania major and Meriones crassus in North Sinai Governorate, Egypt

Zoonotic cutaneous leishmaniasis (ZCL.) now seems to be more than was once thought in North Sinai. In the present study, Meriones crassus (23) and M. sacramenti (10) were collected from limited foci of human CL. Leishmania major (four strains) were isolated from M. crassus as indicated enzymologically by the cellulose acetate electrophoresis of nine different enzymes (MDH, 6 PGD, GD, PK, PGM, NH, GPI, ME and SOD). The four strains were equivalent to zymodeme LON 1 (three strains) and LON 2 (one strain).

Pentastomiasis in Canada

We report a case of human pentastomiasis in a 28-year-old man who emigrated to Canada from Nigeria in 1982 and died as a result of a motor vehicle accident in 1989. At autopsy, in addition to trauma, numerous small cystic nodules (3 to 9 mm in diameter) were discovered in the liver, pleura, lungs, and mesentery and under the intestinal and parietal peritoneum. The parasites were diagnosed as well-preserved, encysted Armillifer armillatus nymphs. Neither degenerative nor inflammatory granulomatous reactions were observed in the adjacent tissue. To our knowledge, this is the first reported case of human infection with encysted nymphs of A armillatus and the eighth reported case of pentastomiasis in North America.

The epidemiology of hydatidosis with special reference to the Mediterranean area

In the Mediterranean area 2 subspecies of Echinococcus granulosus exist: E. g. equinus and E. g. granulosus. The latter is divided into sheep, cattle, pig and camel strains, the adult forms of which mainly occur in farm-dogs but sometimes in wild canidae. Some of these strains can infect man: namely, the sheep and the pig strain. The infectivity of the cattle strains for man is not certain. The epidemiological cycle is mainly a rural one, but it can become sylvatic or even urban. Thus, the epidemiological features of hydatidosis in the Mediterranean area are not basically different from the general epidemiology of the disease. But extensive rearing of sheep, combined with the carelessness and ignorance of people and with some particular habits, favours the maintenance of the infection.

Zoonoses and other findings in hedgehogs (Erinaceus europaeus): a survey of mortality and review of the literature

A survey of mortality in hedgehogs (Erinaceus europaeus) was carried out between July 1976 and November 1986. Most were from Norfolk. Of the 74 examined, 35 (47.3 per cent) were road casualties, one of which yielded Salmonella typhimurium phage type (PT) 104. Of the remaining 39, 13 (33.3 per cent) had salmonellosis due to S enteritidis PT 11. This organism, which appears to be common and widespread in hedgehogs in England was found in 10 separate incidents. The only other zoonosis was ringworm (Trichophyton erinacei infection). Other findings included ectoparasitic infestations with mange mites (Caparinia tripilis), fleas (Archaeopsylla erinacei) and ticks (Ixodes hexagonus). Helminths comprised Crenosoma striatum lungworms (associated with Bordetella bronchiseptica infection in one animal), intestinal nematodes (Capillaria species), cestodes (Rodentolepis erinacei), trematodes (Brachylaemus erinacei) and acanthocephalans (Prosthoryhnchus species). Metaldehyde poisoning was diagnosed in three animals. Over a 10 year period 370 carcases were counted on a stretch of 18 miles of road in Norfolk. The major causes of mortality are probably road casualties and hypothermia during the winter months. In December 1988 S enteritidis PT 11 was isolated from three of four carcases examined in Berkshire and the zoonosis pseudotuberculosis (Yersinia pseudotuberculosis infection) was diagnosed in two of them.

Parasites, pets, and people

It is important for the family physician to understand that patients' relationships with their pets play an important role in helping maintain mental and physical health yet provide the potential for causing illness in the patient. Toxocara canis (dog roundworm) and Toxocara cati (cat roundworm) are the ascarids most commonly responsible for VLM and ocular larva migrans in humans. These roundworms live in their adult stage in the small intestine of the dog and cat where their eggs are passed in the feces. The eggs containing the infective larva are very sticky, thus an infant crawling around on the floor can easily pick these up on fingers that almost invariably end up in the mouth. Infections are usually mild and asymptomatic but with a persistent eosinophilia. Ocular larva migrans is the form usually occurring in older children and adults. Some public health veterinarians recommend that a puppy or kitten should not be obtained as a companion for a child who is not old enough to read, thus bypassing the crawling and toddler stages. Hookworm eggs, shed in the feces of infected dogs or cats, develop into the infective second stage within a week. Humans are usually infected when bare areas of skin such as bare feet or the torso come in contact with soil contaminated with the larvae. The second-stage larvae are able to penetrate the intact skin of humans and the foot pads of dogs and cats. In the United States, the common dog hookworm, A. caninum, is a widespread parasite. Human intestinal ancylostomiasis caused by this species is rare, with only six cases recorded in the literature. Infection in humans or animals by the common tapeworm of dogs and cats (Dipylidium caninum) requires ingestion of the intermediate host, the dog or cat flea containing the larva (cysticercoids) of the agent. Many cases in humans are asymptomatic. Dipylidiasis affects mainly infants and young children who may swallow a flea that hops up while the infant is crawling on the floor or fondling the family pet. Humans appear to be highly resistant to the infection, given the high frequency of flea infestation on dogs and cats and the relative rarity of human disease. Pinworms of animal hosts are not transmissible to humans. Humans become an accidental host of dirofilaria when bitten by an infected mosquito, although the microfilaria will not mature to the adult form in humans. Radio-opaque coin-type lung lesions can be noted on radiographs.(ABSTRACT TRUNCATED AT 400 WORDS)

The human parasite fauna: towards an analysis and interpretation

A breakdown of the human parasite fauna shows approximately 270 species, with almost equal numbers of nematodes, flukes and protozoa and smaller numbers of arthropods and tapeworms. More than 70% are 'adventitious' species for which man is an incidental host. Only 16% are 'core' species, dependent on man for their survival. For 26% man is the usual source of human infection, and for 51% the source is other mammals. A sequence is illustrated showing how parasites may arrive by the host-transfer or co-evolutionary pathways. Adventitious parasites have a narrower geographical range than core species. The richest representation of the major species is in the Aethiopian Zoogeographical Region and the poorest is in the Australasian. Some 14 pairs of closely related forms occur in the main fauna. Some implications of this analysis with respect to man's early history are discussed speculatively.

New aspects of parasitic zoonoses

Selected parasitic zoonoses are discussed with emphasis on epidemiological, diagnostic and some chemotherapeutic aspects. Pneumocystosis, toxoplasmosis, cryptosporidiosis and microsporidiosis are briefly reviewed as "AIDS-related zoonoses". Up to now 5 genera of Microsporidia have been identified as causative agents of human infections, including Encephalitozoon cuniculi, Enterocytozoon bieneusi and Pleistophora sp. which were found in AIDS patients. From the many "other parasitic zoonoses", giardiasis, echinococcosis and taeniosis/cysticercosis are discussed as examples. Significant advances in the understanding of transmission dynamics, in strain characterisation and diagnosis of the diseases have been achieved.

Human conjunctivitis caused by the bird parasite Philophthalmus

We removed a trematode of the species Philophthalmus from under the left upper eyelid of a 66-year-old man who had follicular conjunctivitis for three weeks. After removal of the parasite, the conjunctivitis resolved.

Improvements in the serodiagnosis of helminthic zoonoses

Remarkable progress has been achieved in developing improved serodiagnostic assays for a group of diseases for which other diagnostic methods are often lacking. Toxocariasis, trichinellosis, dirofilariasis, Taenia solium cysticercosis and the cystic and alveolar forms of hydatid disease are occult infections in humans and sometimes in lower animal hosts. Although Strongyloides stercoralis achieves patency in humans, parasitologic diagnosis is often very difficult. Efforts to develop reliable immunodiagnostic methods have spanned several decades but progress had been slow until recently. The complexity and nonspecificity of helminth antigens were major problems which prevented the full realization of the benefits of the highly sensitive assay systems now available. Modern immunologic methods including hybridoma technology, immunoaffinity chromatography and immunoblotting, however, have yielded improved reagents and the means to characterize their nature and function. The outcome of this research has been more sensitive and specific serologic tests based on measurement of both circulating antigens and antibodies as well as improved understanding of the nature of host-parasite interactions. Although much remains to be done, many improved immunodiagnostic procedures are already being applied in clinical diagnosis, epidemiologic studies and control programs directed against the helminthic zoonoses.

[Geographical variability of the causative agent of zoonotic cutaneous leishmaniasis]

A study of the phenetics of the zoonotic cutaneous leishmaniasis agent in Uzbekistan and subzone of southern and northern deserts has made it possible to separate a northern population (or a group of populations) of the agent. It differs from the southern population (or southern ones) in having smaller sizes of the amastigote stage, greater abundance of parasites in cutaneous affections of gerbils, milder progress of leishmaniasis in white mice and great gerbils. This population can be called priaral, i.e. belonging to the subzone of northern deserts of the Turan lowland.

[Pathogenic effect of the trematode Cyclocoeloidea on its hosts]

A study of the ecology of Cyclocoeloidea has shown that true pathogenicity of this group of trematodes is much higher than the known one. In addition to the mechanical damage done by marites of cyclocoeloids to the host, migrations of cyclocoeloid larvae in the definitive host's body are a great threat to the latter as well as processes connected with the removal of sexual production by adult worms outside that results usually in a serious damage to the host's organs and tissues.

Zoonotic cutaneous leishmaniasis in Saudi Arabia: lesions healing naturally in man followed by a second infection with the same zymodeme of Leishmania major

A patient with a previous history of an infection with Leishmania b. braziliensis contracted zoonotic cutaneous leishmaniasis (ZCL) in the Al-Hassa oasis, Eastern Province, Saudi Arabia. Five lesions healed spontaneously over a period of 40 weeks without treatment. A year after acquiring ZCL he became infected again in the same focus. Isolates of parasites at both episodes were identified as L. major, zymodeme LON-4. Compared with the first infection of ZCL, parasites were fewer in the lesions on the second occasion, the lesions were smaller and healing was quicker (10 weeks). This work and a previous report of patients with active lesions and leishmanial scars suggest that second infections of L. major are not uncommon in the oasis where no autochthonous infections of other species of Leishmania have yet been recorded in man and only one species of Phlebotomus (P. papatasi) is known.

Breast nodule produced by Dirofilaria tenuis

A case of Dirofilaria tenuis presenting as a breast nodule is reported in a patient who traveled to the southeast United States 6 months before the nodule was noted. It illustrates an unusual diagnostic problem, especially since it presented in a nonendemic area. The morphological criteria for diagnosis of D. tenuis in tissue sections are noted.