Outcomes in mice with abdominal angiostrongyliasis treated with enoxaparin.

Abdominal angiostrongyliasis (AA) is caused by the nematode Angiostrongylus costaricensis. Parasite-associated thrombosis of mesenteric vessels may lead to intestinal infarction, which might be prevented with anti-thrombotic agents. This study assessed the effect of enoxaparin on survival and pathological findings in Swiss mice with AA. In this experiment, 24 mice were infected with A. costaricensis (10 L3 per animal) followed by treatment with subcutaneous enoxaparin (40 mg/kg/day) or water (sham), starting from 15 days post-infection (dpi) and continued until animal death. Animals were monitored until death or sacrifice at the 50th dpi. Ten mice (42%) were dead after 36 ± 8 dpi. Of these, five (50%) were treated with enoxaparin. Animals treated with enoxaparin and sham did not differ in terms of weight loss (median, 1.3 vs. 4.2 g; P = 0.303) and macroscopical findings. Microscopically, no difference was found in regard to vascular granuloma (median grade, 2 vs. 3; P = 0.293) and presence of either vasculitis (75% vs. 100%; P = 0.217), mesenteric thrombosis (33% vs. 50%; P = 0.680), or bowel necrosis (25% vs. 50%; P = 0.400). Mice dead before the 50th dpi showed more pneumonia (90% vs. 21%; P = 0.002), bowel infarction (40% vs. 0%; P = 0.02), and purulent peritonitis (60% vs. 7%; P = 0.008) compared to survivors. Prophylactic enoxaparin in mice did not prevent tissue damage and mortality related with AA. The lower prevalence of mesenteric thrombosis and bowel infarction regardless of treatment were notorious. Frequent septic complications suggest the need of studies addressing the effect of antibiotics in AA.

Elimination of Angiostrongylus costaricensis larvae in feces from experimentally infected Swiss mice: circadian rhythm and correlation with survival.

Angiostrongylus costaricensis is a nematode which harbors mesentery arteries of rodents. In these animals, a circadian rhythm of elimination of first-stage larvae (L1) and a relation between the amount of L1 in feces and survival are unknown. We assessed fecal elimination of A. costaricensis L1 from experimentally infected Swiss mice and tried to correlate L1 elimination with survival. Thirteen Swiss mice were infected by gavage with ten A. costaricensis L3 larvae obtained from Phyllocaulis slugs. Feces were weighed at 7 A.M: . and 7 P.M: . starting from the 24th day post-infection until animal death. Feces sediment was examined in microscope for L1 counting. The mice were dead after a period ranging 19-61 days post-infection. Compared to diurnal samples, both feces' weight (2.3 ± 0.7 vs. 1.8 ± 0.5 g; P < 0.0001) and L1 total count [median 1,950 vs. 1,250; P = 0.015] were higher in feces eliminated at night. No difference was observed between diurnal and nocturnal elimination when counting L1 by gram of feces (725 vs. 650 L1/g; P = 0.821). A significant correlation was observed between survival and total number of L1 in feces (r = 0.84; P = 0.0007). This study suggests that mice experimentally infected with A. costaricensis eliminate more L1 at night due to higher fecal volume at this period. The correlation between number of L1 in feces and survival suggests a phenomenon of tolerance to A. costaricensis infection in mice with longer survival.

Dogs may be a reservoir host for Angiostrongylus costaricensis.

Angiostrongylus costaricensis is a parasitic nematode of wild rodents. Several other vertebrate species including man may become infected by ingestion of the third stage larvae produced by the intermediate hosts, usually slugs from the family Veronicellidae. There is a report of the diagnosis of abdominal angiostrongyliasis in Canis familiaris with lesions resembling those found in human disease. As a preliminar evaluation of the adequacy of a canine model for pathogenetic studies, a dog was inoculated with 75 L3 of A. costaricensis. Infection was established and fist stage larvae were found in feces up to 88 days post infection, sometimes in very large numbers (9.5 x 10(4) L1/g). No clinical manifestations or significant lesions were detected. These are indications that dog may play a role as a reservoir host for A. costaricensis.

Dogs may be a reservoir host for Angiostrongylus costaricensis

Angiostrongylus costaricensis is a parasitic nematode of wild rodents. Several other vertebrate species including man may become infected by ingestion of the third stage larvae produced by the intermediate hosts, usually slugs from the family Veronicellidae. There is a report of the diagnosis of abdominal angiostrongyliasis in Canis familiaris with lesions resembling those found in human disease. As a preliminar evaluation of the adequacy of a canine model for pathogenetic studies, a dog was inoculated with 75 L3 of A. costaricensis. Infection was established and fist stage larvae were found in feces up to 88 days post infection, sometimes in very large numbers (9.5 x 10(4) L1/g). No clinical manifestations or significant lesions were detected. These are indications that dog may play a role as a reservoir host for A. costaricensis