Luis A. Gomez-Puerta

A high oxfendazole dose to control porcine cysticercosis: Pharmacokinetics and tissue residue profiles

Oxfendazole (OFZ) is efficacious for porcine cysticercosis at 30 mg/kg. OFZ is not registered to be used at this dose. The assessment of the OFZ and metabolites [(fenbendazole sulphone (FBZSO2), fenbendazole (FBZ)] plasma pharmacokinetic and tissue residue profiles after its oral administration to pigs and the withdrawal period for human consumption were reported. Forty-eight pigs allocated into two groups received OFZ (30 mg/kg) orally as a commercial (CF) or as experimental formulation (SMF). Samples (blood, muscle, liver, kidney and fat) were collected over 30 days post-treatment and analyzed by HPLC. OFZ was the main compound recovered in plasma, followed by FBZSO2 and low FBZ concentrations. OFZ AUC0-LOQ (209.9±33.9 μg·h/ml) and Cmax (5.40±0.65 μg/ml) parameters for the CF tended to be higher than those for the SMF (AUC0-LOQ: 159.4±18.3 μg h/ml, Cmax: 3.80±0.35 μg/ml). The highest total residue (OFZ+FBZSO2+FBZ) concentrations were quantified in liver, followed by kidney, muscle and fat tissue. FBZSO2 residue levels were the highest found in muscle (0.68±0.39 μg/g) and fat (0.69±0.39 μg/g). In liver and kidney the highest residues corresponded to FBZ (5.29±4.36 μg/g) and OFZ (2.86±0.75 μg/g), respectively. A withdrawal time of 17 days post-treatment was established before tissues are delivered for human consumption.

Longevity and viability of Taenia solium eggs in the digestive system of the beetle Ammophorus rubripes

The present study evaluated the capacity of Ammophorus rubripes beetles to carry Taenia solium eggs, in terms of duration and viability of eggs in their digestive system. One hundred beetles were distributed into five polyethylene boxes, and then they were infected with T. solium eggs. Gravid proglottids of T. solium were crushed and then mixed with cattle feces. One gram of this mixture was placed in each box for 24 hours, after which each group of beetles was transferred into a new clean box. Then, five beetles were dissected every three days. Time was strongly associated with viability (r=0.89; P<0.001) and the calculated time to cero viability is 36 days. The eggs in the intestinal system of each beetle were counted and tested for viability. Taenia solium eggs were present in the beetles digestive system for up to 39 days (13th sampling day out of 20), gradually reducing in numbers and viability, which was 0 on day 36 post-infection. Egg viability was around 40% up to day 24 post-infection, with a median number of eggs of 11 per beetle at this time. Dung beetles may potentially contribute towards dispersing T. solium eggs in endemic areas.

Occurrence of Giardia duodenalis assemblages in alpacas in the Andean region

In this study, 352 fecal samples were analyzed for G. duodenalis from alpaca mothers and crias from three different areas of highland in Peru. The triosephosphate isomerase (TPI) gene of Giardia was amplified using a nested PCR protocol. Forty-six G. duodenalis-PCR positive samples were sequenced. G. duodenalis assemblage A was the most frequent followed by assemblage E. The former was seen in 37 animals whereas the latter was seen in nine. Most of the assemblage A infections were caused by the A1 subtype of sub-assemblage AI, except for three, which were caused by the A2 subtype of sub-assemblage AI. Assemblage A was found in all three geographic regions, while assemblage E was detected in crias from two regions. Among the four alpaca mothers positive for Giardia, three had assemblage AI and one had assemblage AII. Results of this study indicate that possible zoonotic transmission human to alpacas.

Polycystic echinococcosis in Pacas, Amazon region, Peru.

In the Peruvian Amazon, paca meat is consumed by humans. To determine human risk for polycystic echinococcosis, we examined wild pacas from 2 villages; 15 (11.7%) of 128 were infected with Echinococcus vogeli tapeworms. High E. vogeli prevalence among pacas indicates potential risk for humans living in E. vogeli–contaminated areas.

New insights in cysticercosis transmission.

Taenia solium infection causes severe neurological disease in humans. Even though infection and exposure to swine cysticercosis is scattered throughout endemic villages, location of the tapeworm only explains some of the nearby infections and is not related to location of seropositive pigs. Other players might be involved in cysticercosis transmission. In this study we hypothesize that pigs that carry nematodes specific to dung beetles are associated with cysticercosis infection and/or exposure. We carried out a cross-sectional study of six villages in an endemic region in northern Peru. We euthanized all pigs (326) in the villages and performed necropsies to diagnose cysticercosis. For each pig, we counted cysticerci; measured anti-cysticercus antibodies; identified intestinal nematodes; tabulated distance to nearest human tapeworm infection; and recorded age, sex, productive stage, and geographic reference. For the purpose of this paper, we defined cysticercosis infection as the presence of at least one cysticercus in pig muscles, and cysticercosis exposure as seropositivity to anti-cysticercus antibodies with the presence of 0–5 cysticerci. Compared to pigs without nematode infections, those pigs infected with the nematode Ascarops strongylina were significantly associated with the presence of cysticerci (OR: 4.30, 95%CI: 1.83–10.09). Similarly, pigs infected with the nematode Physocephalus sexalatus were more likely to have cysticercosis exposure (OR: 2.21, 95%CI: 1.50–3.28). In conclusion, our results suggest that there appears to be a strong positive association between the presence of nematodes and both cysticercosis infection and exposure in pigs. The role of dung beetles in cysticercosis dynamics should be further investigated.

Efficacy of a single oral dose of oxfendazole against Fasciola hepatica in naturally infected sheep.

The efficacy of a single oral dose of 30 mg/kg of oxfendazole against Fasciola hepatica was evaluated in a controlled study in naturally infected sheep. Sheep were diagnosed by stool microscopy after sedimentation, and positive animals were randomized to oxfendazole (N = 20) or no treatment (N = 20). A new stool exam was performed 10 days after treatment. All stool microscopies were performed masked to the treatment group. No side effects were noticed. All sheep in the control group remained infected with similar counts of eggs per gram of stools. None of the animals in the treatment group showed Fasciola eggs in stools after 10 days of treatment. A single dose of oxfendazole is highly effective against F. hepatica, providing a new drug alternative for the control of fascioliasis or integrated zoonosis control.

Occurrence of tapeworm Bertiella mucronata (Cestoda: Anoplocephalidae) in the Titi monkey Callicebus oenanthe from Peru: New definitive host and geographical record

The presence of the cestode Bertiella mucronata (Cestoda: Anoplocephalidae) is described from the small intestine of two Titi monkeys Callicebus oenanthe, from the Indañe community in Moyobamba, Peru. Six additional cestodes were studied and identified as B. mucronata. This finding constitutes the first report of the cestode in Peru and demonstrates that C. oenanthe is a new definitive host for this parasite.

Molecular and morphological evidence of Taenia omissa in pumas (Puma concolor) in the Peruvian Highlands

A total of 41 cestodes were collected during necropsy examination on 2 pumas (Puma concolor) that were found in 2 communities in Canchis province, Cuzco region, Peru, at 4500 meters above sea level (Peruvian Andes). The cestodes were evaluated morphologically and molecularly. A fragment of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1) was used as a genetic marker. All the cestodes were identified as Taenia omissa. In the present report, we give a brief description by molecular and morphological diagnosis of the cestodes and compare nucleotide sequences with previous isolates from GenBank. Upon comparison, the sequences showed a difference in the cox1 gene of 5.1 to 5.3% with other teniids sequences. This finding constitutes the first report of T. omissa in Peru and expands the geographic distribution of this parasite.

Trombiculiasis caused by chigger mites Eutrombicula (Acari: Trombiculidae) in Peruvian alpacas.

Trombiculiasis is an infestation caused by larvae members of the family Trombiculidae, common called chigger mites. In this study is presented the first case of trombiculiasis caused by the infestation of chigger mite Eutrombicula in alpacas from Peru. Twenty-two alpacas of a total of 130 animals were infested by Eutrombicula sp. The chigger mite location was only in the face skin folds and around the eyes. In addition, all alpacas infested had alopecia and dermatitis in the infected zone.

Presence of Porocephalus clavatus (Arthropoda: Porocephalidae) in Peruvian Boidae snakes

The pentastome species, Porocephalus clavatus, has been found to infect the lungs of two species of snakes in the family Boidae family (Boa constrictor and Epicrates cenchria). The individual of B. constrictor was collected in the Amazonian rainforest of Departamento Loreto, Peru. The E. cenchria was recovered from the pet trade in Lima, Perus capital city. A total of 22 P. clavatus were collected and examined from these two snakes. This is the first report of P. clavatus in Peru. The morphology of the parasites and the possible importance in public and animal health are discussed.