Márcia Bohrer Mentz

Drug trials for treatment of human angiostrongyliasis

Abdominal and cerebral angiostrongyliasis are two important infections produced by metastrongylid worms, the former occurring in Central and South America and the later in Asia and Pacific Islands. Drug treatment is a challenge since the worms and its evolving larvae live or migrate inside vessels and efficient killing of the parasites may produce more severe lesions. Larvicidal effect of certain drugs appears to be more easily accomplished but this outcome is not useful in abdominal angiostrongyliasis since clinical manifestations appear to result from sexual maturation of the worms. We review the drug trials in murine experimental models and conclude that most of them could not be considered good candidates for treatment of human infection, except for PF1022A, pyrantel and flubendazole.

Human ocular sparganosis in southern Brazil

We report the first case of human ocular sparganosis in the state of Santa Catarina, southern Brazil. A young female patient presented with three periocular moveable inflammatory masses in her right eye, during two years. By surgical excisional biopsy, a helminth larval stage was removed and identified as sparganum. Clinical, laboratory and epidemiological data on this parasite are presented.

Treatment with mebendazole is not associated with distal migration of adult Angiostrongylus costaricensis in the murine experimental infection

Abdominal angiostrongyliasis is a zoonotic infection produced by a metastrongylid intra-arterial nematode, Angiostrongylus costaricensis. Human accidental infection may result in abdominal lesions and treatment with anti-helminthics is contra-indicated because of potential higher morbidity with excitement or death of worms inside vessels. To evaluate the effect of mebendazole on localization of the worms, male Swiss mice, 5 week-old, were infected with 10 third stage larvae per animal. Twelve infected mice were treated with oral mebendazol, at 5 mg/kg/day, for 5 consecutive days, begining 22 days after inoculation. As control groups, 12 infected but non-treated mice and other 12 non-infected and non-treated mice were studied. The findings at necropsy were, respectively for the treated (T) and control (C) groups: 92% and 80% of the worms were inside the cecal mesenteric arterial branch; 8% and 10% were located inside the aorta. Only in the group C some worms (10%) were found inside the portal vein or splenic artery. These data indicate that treatment with mebendazole does not lead to distal or ectopic migration of A. costaricensis worms.

Viabilidade de ovos de Fasciola hepatica de bovinos em sistema de biodigestão anaeróbia

Cattle Fasciola hepatica egg-viability was studied in closed system of anaerobic biodigestion. Two thirds of a biodigestor were filled with liquefied manure from eight Hosltein cows, naturally infected. For 10 consecutive weeks of observation, the biodigestor internal temperature ranged from 24oC to 28oC, and external temperature from 26oC to 33oC. All the effluent samples showed a constant pH of 7. The samples of the effluent were weekly collected, in a total of 10 and submitted to techniques to detect the presence and viability of the trematode eggs. It was detected a 42-day egg viability. Therefore, liquefied cattle manure containing Fasciola hepatica eggs must remain under anaerobic biodigestion for at least 42 days before its safe return to the environment.

Rhipicephalus sanguineus (ACARI: IXODIDAE) BITING A HUMAN BEING IN PORTOALEGRE CITY, RIO GRANDE DO SUL, BRAZIL.

We report the finding of a female brown dog tick, Rhipicephalus sanguineus (Acari: Ixodidae) on the scalp of a male patient in Porto Alegre, Rio Grande do Sul, Brazil. Human parasitism by this tick is rare and has seldomly been reported in the literature, despite its recognized importance since it can act as a vector of Rickettsia rickettsii, the agent of spotted fever.

Viability of Bovine`s Strongyloidea eggs in a System of Anaerobic Biodigestion

Cattle Strongyloidea egg-viability was studied in closed system of anaerobic biodigestion. Two thirds of a biodigestor were filled with liquified manure from eight Hosltein cows, nacturally infected. For 10 consecutive weeks of observation, the biodigestor internal temperature varied from 24oC to 28oC and external temperature, from 26oC to 33oC. All the effluent samples showed a constant pH of 7. The samples of the effluent were weekly collected, in a total of 10, and submitted to techniques to detect the presence and viability of the helminth eggs. It was detected a 35-day egg viability. The infective larvae of Haemonchus, Cooperia and Oesophagostomum genus were found until the 14th day of observation and the infective larvae of Trichostrongylus and Ostertagia genus, until the 35th day. Therefore, liquefied cattle manure containing Strongyloidea eggs must remain under anaerobic conditions for at least 35 days before its safe return to the environment.

Dermatitis caused by the tropical fowl mite Ornithonyssus bursa (Berlese) (Acari: Macronyssidae): a case report in humans

We herein report human dermatitis caused by the tropical fowl mite Ornithonyssus bursa (Berlese). The cases occurred in an apartment in a residential district of Porto Alegre City, State of Rio Grande do Sul, Brazil, where three members of the same family presented with pruritic lesions on the arms and legs. On inspecting the bathroom, several mites measuring approximately 1.0mm in length were observed coming from a nest of Rufous Hornero, Furnarius rufus (Gmelin). This is the first report of O. bursa in the urban area of Porto Alegre City, from a nest of F. rufus that bites humans.

In vitro maintenance of Angiostrongylus costaricensis does not provide physiological conditions for egg laying.

Fifteen pairs (male/female) of Angiostrongylus costaricensis were kept in vitro in Waymouth medium for three days to evaluate the amount and duration of egg laying. At 24, 48 and 72 hours, the mean egg counts were 321, 24 and 4 eggs/10 microliters, respectively. Most of the eggs were eliminated within the first 24 hours, suggesting they are expelled under non-physiological conditions. These results indicate that in vitro conditions are not appropriate for drug trials of egg-laying inhibitors for treatment of abdominal angiostrongylosis.

SUSCEPTIBILITY AND MORBIDITY BETWEEN MALE AND FEMALE SWISS MICE INFECTED WITH Angiostrongylus costaricensis

The gender of vertebrate hosts may affect the outcome of parasitic infections. An experimental murine infection with Angiostrongylus costaricensis was followed with determinations of body weight, fecal larval elimination, number and length of adult worms, number of macroscopic intestinal lesions, and mortality. Groups of male and female Swiss mice were infected with 10 3(rd)-stage A. costaricensis larvae per animal. The results indicate there are no significant differences related to gender of the host, except for higher length of worms developed in male mice.