César Álvarez-Guerrero

Universidad Autónoma de Nayarit, Nayarit, Nayarit, Mexico

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Publications (4)6.27 Total impact

  • C. Alvarez-Guerrero · M.A. Muñoz-Guzmán · F. Alba-Hurtado ·
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    ABSTRACT: This study aims to describe some of the unknown pathological and parasitological traits of experimental feline gnathostomosis. Thirteen female cats were orally inoculated with 30 advanced third-stage Gnathostoma binucleatum larvae and were euthanized at various post-infection (p.i.) periods. Clinically, the cats presented with nausea, vomiting, abdominal pain and other nonspecific signs. None of the cats shed eggs in their fecal matter. One cat, euthanized at 6 months p.i., developed a fibrous vascular nodule 2-3 cm in diameter within its gastric wall. The nodule contained caverns filled with mucous and bloody fluid as well as a juvenile worm. The histological characteristics of the nodule were observed, and the morphology of the juvenile worm was revealed using scanning electron microscopy. Another cat, euthanized at 10 months p.i., was found to have a larva within its diaphragm. Infected cats developed increased antibody titers against antigens of G. binucleatum adults and larvae beginning in the first month p.i., and these titers were maintained until the end of the experiment, suggesting the presence of undetected migrating larvae. The low number of cats with parasites and poor development of the parasites found suggest that cats have a low susceptibility to infection by G. binucleatum and cast doubt on the importance of domestic cats in maintaining the biological cycle of this parasite in nature.
    Veterinary Parasitology 08/2014; 204(3-4). DOI:10.1016/j.vetpar.2014.04.027 · 2.46 Impact Factor
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    César Álvarez-Guerrero · Marco Antonio Muñoz-Guzmán · Fernando Alba-Hurtado ·
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    ABSTRACT: Stages of the parasite were detected in the gastric wall of four female dogs infected with Gnathostoma binucleatum larvae. One showed a nodule with adult worms inside, two had nodules with larvae and the other one had juvenile stages without nodules. Pre-patent period in the bitch with adult worms was 22 weeks and patent period was 14 weeks. Egg morphology and clinical profile were described. In the bitch with adult worms, a 57 x 24 mm cavernous mass was detected by ultrasonography in the stomach wall and by endoscopy the mass was detected projecting into the gastric lumen. Antibodies against larvae antigens increased (P < 0.05) after the second pi month; Western blot showed a sequential recognition of the antigens. Results provide useful data for canine gnathostomosis diagnosis.
    Veterinaria Mexico 03/2012; 43(1):17-28. · 0.32 Impact Factor
  • Cesar Álvarez-Guerrero · Fernando Alba-Hurtado ·
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    ABSTRACT: To diminish the risk of transmission to humans of advanced third-stage larvae (A3L) of Gnathostoma binucleatum in fish foods, we evaluated the effects of some physical factors on larval viability. A3L protected within fish meatballs were subjected to freezing, refrigeration, boiling, dry heat, and immersion in lemon juice. By freezing, larvae were killed in 48 h, by refrigeration after 30 days, by boiling in 4 min, and by broiling for 60 min. By lemon juice immersion (pH 2.5), encysted larvae were killed after 5 days and nonencysted larvae in 7 h. Results show that freezing fish at -10 to -20°C for 48 h, or cooking fish by frying, boiling, or broiling, will prevent transmission of G. binucleatum. Furthermore, results dispel the popular myth that lemon juice kills encysted larvae in fish.
    Journal of food protection 05/2011; 74(5):844-8. DOI:10.4315/0362-028X.JFP-10-321 · 1.85 Impact Factor
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    ABSTRACT: Lesions and antibody kinetics produced by inoculation of Gnathostoma binucleatum larvae into dogs are described, as well as the morphology of the recovered parasites. In four out of five infected bitches parasite phases were found in the stomach. Only one bitch eliminated eggs and adult parasite phases in feces. In this bitch, the prepatency period lasted 22 weeks and the patency period 14 weeks. Necropsy results showed a copiously vascularized 8-cm diameter fibrous nodule lodged in the greater curvature of the stomach. Two bitches that eliminated no eggs showed 1- to 2-cm diameter nodules on the gastric wall, with five juvenile phases in each. One bitch that eliminated no eggs and exhibited no gastric nodules showed juvenile parasites on the gastric wall. Results confirm dogs as definitive hosts of this parasite. New data on the pathological and parasitological aspects of canine gnathostomosis are presented.
    Experimental Parasitology 01/2011; 127(1):84-9. DOI:10.1016/j.exppara.2010.06.038 · 1.64 Impact Factor
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    ABSTRACT: In order to clarify the specific identity of the etiological agent of human gnathostomosis in Nayarit State, Mexico, morphological and molecular studies were conducted on advanced third stage larvae obtained from human and fish tissue. Cathorops fuerthii from Agua Brava lagoons complex, was the only fish species found to be infected among four species surveyed. Morphological variability does not allow specific identification of the larvae. Internal transcribed spacer 2 of the ribosomal DNA was sequenced for six larvae (five from fish, one from human tissue). Low divergence in the sequences of Nayarit larvae and Gnathostoma binucleatum (0.24% or less) indicate that the larvae examined belong to this species.
    Parasitology International 07/2002; 51(2):201-4. DOI:10.1016/S1383-5769(02)00014-4 · 1.86 Impact Factor