N. Casado

Randomised controlled trial of efficacy of albendazole in intra-abdominal hydatid disease

The efficacy of albendazole in hydatid disease is still unclear, because there has been no study that assessed the status of the parasite after treatment. The significance of albendazole-induced echographic changes in the cyst therefore cannot be judged. We did a prospective, controlled, randomised, open study of albendazole in patients with liver hydatid disease, and assessed parasite viability after treatment. 18 patients received no albendazole treatment (controls), 18 received albendazole (10 mg/kg daily) for 1 month (group A), and 19 received the drug for about 3 months (group B). Echography was done before and during treatment; all patients underwent surgery on completion. Parasite (protoscolex viability and development of cysts in mice) and ultrastructure studies were done for all cysts removed. 8 (50%) of cysts in the control group, 13 (72%) in group A, and 16 (94%) in group B were non-viable (p = 0.015). Protoscolex and cyst viability were significantly (p = 0.039 and p = 0.018, respectively) lower in treated patients than in controls. Treatment was also significantly associated with total cyst membrane disintegration. 68% of cysts treated for 3 months showed echographic changes, and only 1 of 20 cysts showing echographic changes during treatment was judged viable. The efficacy of albendazole at a dose of 10 mg/kg daily for 3 months suggests that it is a suitable alternative to surgery in uncomplicated hydatid liver disease, as initial treatment.

In vitro effect of praziquantel and albendazole combination therapy on the larval stage of Echinococcus granulosus

Abstract Protoscolices of Echinococcus granulosus were incubated in vitro with praziquantel (PZ), albendazole (ABZ), or a combination of both (PZ + ABZ). PZ and ABZ displayed slower protoscolicidal activity when applied separately than when used in combination. Despite the low PZ + ABZ concentrations used, protoscolex viability dropped rapidly (within 15 days). At this time, cysts did not develop following their inoculation into mice. The ultrastructural changes induced in the protoscolices by PZ + ABZ were (a) the loss of sucker concavity, (b) tegumental contraction of the soma region, (c) the formation of digitiform tegumental extensions, (d) destruction of the tegument, and (e) the degeneration of parenchyma cells as reflected by the presence of numerous lamellar bodies. The PZ + ABZ treatment was effective only against small cysts, which had collapsed at 10 days postinoculation (p.i.). This treatment caused the following alterations: (a) loss of cyst turgidity at 6 days p.i.; (b) separation of the laminated and germinal layers; (c) loss of microtriches; (d) the appearance of numerous lipid droplets in the inner region of the germinal layer; (e) vacuolation of the cyton cytoplasm; and (f ) the formation of abundant autophagosomes, which finally led to loss of the integrity of the germinal layer.

A molecular survey of Piroplasmida and Hepatozoon isolated from domestic and wild animals in Burgos (northern Spain)

This study reports a molecular survey of Hepatozoon species and of the order Piroplasmida in the Province of Burgos, northern Spain. The diagnostic techniques employed included PCR and the sequencing of the 18S rRNA gene. Eighty-nine blood samples from domestic animals plus 138 blood/coagulated blood samples from wild mammals were examined. Theilerid protozoa were found at relatively high frequencies in bovines (14.6%) and horses (36%). Theileria buffeli, T. sergenti and T. annulata were diagnosed in cows. T. equi was common in horses and T. annae was found in a donkey for the first time. A new piroplasmid was found in the European badger (20%). This appears to be distantly related to both T. annae and a piroplasmid isolated from Lontra canadensis. A moderate prevalence (14%) for T. annae was recorded in red foxes. A species of hepatozoon was found in one bank vole (17%), while 28% of the red foxes examined were found to be infected with H. canis. Twenty-five wild house mice were studied and found not to be carriers of piroplasmids or Hepatozoon species. Wild boars, roe deer, hares, Apodemus sp. and moles were also negative for haematozoan infection. The present study indicates that piroplasmid protozoa are present at a low to moderate frequency in some domestic herbivores in the Burgos area. They also infect certain wild mammalian species, which may act as zoonotic carriers.

The effects of albendazole and albendazole sulphoxide combination-therapy on Echinococcus granulosus in vitro

Protoscoleces of Echinococcus granulosus were incubated in vitro with decreasing concentrations of either albendazole (ABZ) or albendazole sulphoxide (ABZ.SO) (50, 10, 1 and 0.1 micrograms ml-1), and in combination. Viability was assessed by the methylene blue exclusion test and establishment of infection in mice. Protoscolex ultrastructure was determined by means of transmission and scanning electron microscopy. ABZ and ABZ.SO, when used separately had protoscolicidal activity after a longer incubation period (30 days) than when used as combined compounds. When incubated in the presence of ABZ + ABZ.SO, protoscolex viability dropped rapidly. That is, protoscoleces were all non-viable at 12 days of exposure, with no cyst developing following their inoculation into mice. The ultrastructural changes induced by ABZ or ABZ.SO alone, were: (a) rostellar disorganization, (b) formation of numerous blebs on the tegument, (c) loss of the microtriches, (d) increased vesiculation within the tegumentary cytons together, (e) an increase in lipid deposits and (f) depletion of glycogen reserves. After incubation with combined ABZ and ABZ.SO the tegument contained numerous blebs which became detached, leaving debris only, some intact nuclei being discernible in the protoscolex parenchyma.

Development of a chemotherapeutic model for the in vitro screening of drugs against Echinococcus granulosus cysts: the effects of an albendazole-albendazole sulphoxide combination

This paper describes a novel experimental model for the screening of putative drugs against the metacestode stage of E. granulosus using hydatid cysts derived from in vitro culture of protoscoleces. The effects of an ABZ+ABZ.SO combination against cultured and murine cysts were studied with this in vitro model system. This treatment produced loss of turgidity of the cultured cysts in less time than in the murine cysts but the ultrastructural tissue damage observed in both cultured and murine cysts was similar. The ultrastructural changes induced by ABZ+ABZ.SO were: (i) vacuolation of the distal cytoplasm that extended to the tegumentary cells of the germinal membrane; (ii) increased number of mitochondria; (iii) partial loss of microtriches; (iv) increased number of autophagosomes; and (v) an increase in lipid deposits.

Echinococcus granulosus: praziquantel treatment against the metacestode stage

Abstract The efficacy of praziquantel against the metacestode of Echinococcus granulosus was studied by means of in vitro incubations or in vivo experiments. The results of in vitro incubations indicated that the effectiveness of praziquantel was higher when the parasite material comprised cysts from cyst masses than in the case of intact cysts that retained their adventitial layer. Ultrastructural alterations in the germinal layer of collapsed cysts incubated in vitro were detected. The results obtained in mice after 4 months of treatment demonstrated no significant difference between the control and treated groups with regard to the number and wet weight of developed cysts. However, ultrastructural alterations were detected in the cyst tissue that were similar to those described in the in vitro experiment. In contrast, the effect of chemoprophylaxis on the number and the wet weight of developed cysts was extremely significant as compared with the control value, the efficacy being 99.41% and 98.32%, respectively. Moreover, ultrastructural observations of the cyst tissue revealed loss of its integrity, and no intact cyton was observed in the germinal layer of the developed cyst.

Molecular detection of hemoprotozoa and Rickettsia species in arthropods collected from wild animals in the Burgos Province, Spain

Limited information on the presence of bacterial and hematozoan infections in parasitic arthropods from Spain is available. In an attempt to address this issue, the prevalence of Theileria, Babesia, Hepatozoon, and Rickettsia species was investigated by polymerase chain reaction plus sequencing. In a survey for zoonotic pathogens in ectoparasites, 42 wild animals (which included rodents, carnivores, Sciuridae, and Cervidae) were captured in Burgos (Spain). A total of 256 arthropods (including 107 ticks, 76 fleas, and 73 mites) were collected from these mammals. Molecular diagnostic results showed that (i) Rickettsia felis was found in fleas (two Ctenocephalides felis), (ii) Hepatozoon sp. infected some fleas (two Ctenophtalmus sp. and a DNA pool of Ceratophyllus sciurorum) and Acari (one Neotrombicula sp.), and (iii) Theileria annae was found in Ixodes ricinus and I. hexagonus (each a single infected specimen). All microorganisms and parasites were genetically identical to pathogens already described in Spain or elsewhere. Infected arthropods were recovered from beech marten, bank vole, squirrel, wood mouse, and red fox. Our findings emphasize the potential risk for transmission of rickettsias to humans (namely, R. felis) in Burgos, since C. felis is capable to seek out humans for feeding. No hemoprotozoa with proven significance as human pathogens were found in the survey. However, finding T. annae in ticks recovered from wild canids suggests possible links of sylvatic and domestic cycles for some Piroplasmida.

In vitro effects of levamisole and ivermectin against Echinococcus granulosus protoscoleces

The in vitro effects of levamisole and ivermectin against Echinococcus granulosus protoscoleces were studied by means of light and electron microscopy. Both drugs had a protoscolicidal activity that increased proportionally with increasing concentrations of the drugs. Ivermectin showed the more rapid effects and caused contraction and paralysis of protoscoleces. A paralyzing effect was also observed with levamisole, followed by irreversible tissue vacuolation leading to death.

Praziquantel and albendazole in the combined treatment of experimental hydatid disease.

Abstract The combination of praziquantel and albendazole (PZ + ABZ) used in the present study demonstrated an efficacy of 100% when used as chemoprophylactic treatment because no viable hydatid cysts developed after mice had been injected with protoscolices. However, when the PZ + ABZ combination was used for the treatment of 4-month secondary experimental hydatidosis, no significant difference was found between the control and treated mice, although severe damage to the cyst ultrastructure of the treated mice was observed.

In vivo effect of oral albendazole and albendazole sulphoxide on development of secondary echinococcosis in mice

This paper describes the effectiveness of ABZ, ABZ.SO and ABZ + ABZ.SO treatment in mice infected with Echinococcus granulosus protoscoleces. The results were evaluated in two ways: measuring the number and wet weight of developed cysts and by transmission electron microscopy (TEM) of tissue cyss. ABZ and ABZ + ABZ.SO had an important effect upon larval growth in E. granulosus. The ultrastructural changes noted were: vacuolation of tegumentary cells of the germinal membrane; increased number of mitochondria; increased number of autophagosomes and an increase in lipid deposits.