RESUMEN
Hymenolepis nana is a common intestinal tapeworm that affects humans. Drugs are available for the treatment of this infection, including praziquantel (PZQ), nitazoxanide and niclosamide. Although the drug of choice is praziquantel, due to its high cure rates, indicators of the development of PZQ resistance by different parasites have begun to appear over recent decades. Therefore, this study was a trial to find an alternative to PZQ by assessing the activity of the crude aqueous extract of the medicinal herb Artemisia absinthium against H. nana. In vitro, the extract was used against adult worms at concentrations of 1 and 5 mg/ml, in comparison with 1 mg/ml of PZQ. The times of worm paralysis and death were determined. Ultrastructural morphological changes were studied using transmission electron microscopy (TEM). For the in vivo study, infected mice were divided into untreated, PZQ-treated and A. absinthium-treated groups (400 mg/kg and 800 mg/kg). Pre- and post-treatment egg counts per gram of faeces (EPG) were performed; then, the reduction percentages of the EPG and worm burden were calculated. The best results were obtained with praziquantel. Artemisia absinthium induced worm paralysis, death and ultrastructural alterations, such as tegumental damage, lipid accumulation, and destruction of the nephridial canal and the intrauterine eggs, in a dose-dependent manner. Additionally, significant reductions in the EPG and worm burden were recorded in A. absinthium-treated mice. Although the results obtained with A. absinthium were promising and comparable to PZQ, further studies using different extracts, active ingredients and concentrations against different parasites should be conducted.
Asunto(s)
Artemisia absinthium/química , Hymenolepis nana/efectos de los fármacos , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Praziquantel/farmacología , Praziquantel/uso terapéutico , Animales , Antihelmínticos/administración & dosificación , Antihelmínticos/farmacología , Antihelmínticos/uso terapéutico , Heces/parasitología , Himenolepiasis/tratamiento farmacológico , Himenolepiasis/parasitología , Hymenolepis nana/ultraestructura , Ratones , Microscopía Electrónica de Transmisión , Recuento de Huevos de Parásitos , Extractos Vegetales/administración & dosificación , Praziquantel/administración & dosificaciónRESUMEN
Hymenolepis nana and Hymenolepis diminuta are globally widespread zoonotic cestodes. Rodents are the main reservoir host of these cestodes. Brown rats (Rattus norvegicus) are the best known and most common rats, and usually live wherever humans live, especially in less than desirable hygiene conditions. Due to the little information of the 2 hymenolepidid species in brown rats in China, the aim of this study was to understand the prevalence and genetic characterization of H. nana and H. diminuta in brown rats in Heilongjiang Province, China. Total 114 fecal samples were collected from brown rats in Heilongjiang Province. All the samples were subjected to morphological examinations by microscopy and genetic analysis by PCR amplification of the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene and the internal transcribed spacer 2 (ITS2) region of the nuclear ribosomal RNA gene. In total, 6.1% (7/114) and 14.9% (17/114) of samples were positive for H. nana and H. diminuta, respectively. Among them, 7 and 3 H. nana isolates were successfully amplified and sequenced at the COX1 and ITS2 loci, respectively. No nucleotide variations were found among H. nana isolates at either of the 2 loci. Seventeen H. diminuta isolates produced 2 different COX1 sequences while 7 ITS2 sequences obtained were identical to each other. The present results of H. nana and H. diminuta infections in brown rats implied the risk of zoonotic transmission of hymenolepiasis in China. These molecular data will be helpful to deeply study intra-specific variations within Hymenolepis cestodes in the future.
Asunto(s)
Hymenolepis diminuta/aislamiento & purificación , Hymenolepis nana/aislamiento & purificación , Ratas/parasitología , Animales , Secuencia de Bases , China/epidemiología , Complejo IV de Transporte de Electrones/genética , Heces/parasitología , Humanos , Himenolepiasis/epidemiología , Himenolepiasis/parasitología , Himenolepiasis/transmisión , Hymenolepis diminuta/genética , Hymenolepis diminuta/ultraestructura , Hymenolepis nana/genética , Hymenolepis nana/ultraestructura , Mitocondrias/enzimología , Mitocondrias/genética , Reacción en Cadena de la Polimerasa , Prevalencia , ARN de Helminto/genética , ARN Ribosómico/genética , Zoonosis/epidemiología , Zoonosis/parasitologíaRESUMEN
Hymenolepis nana (H. nana) is the most common tapeworm infection worldwide. It is more prevalent in warm climates where sanitation is poor, particularly among children. The effect and mechanism of action of praziquantel (PZQ), given at a dose of 25-mg/kg BW, and Carica papaya dried seed crude aqueous extract (CAE), given at a dose of 1.2-g/kg BW, were assessed on H. nana worms in experimentally infected mice. Tegumental changes were studied using the scanning electron microscope (SEM) and different parasitological parameters were observed. Each group of infected mice was divided into two subgroups. The first subgroup received either treatment before the 4th day after infection to investigate their effects on the cysticercoid stage. The other subgroup received treatments after the development of the adult stage, confirmed by eggs detection in stool. Both PZQ and C. papaya dried seed CAE resulted in a significant reduction of worm burden, total egg output and viable egg count. Marked tegumental changes were evident in adult worms treated with either treatment including shrinkage of the scolex and neck region with rostellar edema and complete loss of its hooks. However, all previous effects were exerted more rapidly in the case of PZQ treatment. They both significantly reduced cysticercoid stage size. Nevertheless, C. papaya outstand PZQ in having a deforming effect on adults arising from treated cysticercoids. It was concluded that C. papaya has significant anti-cestodal properties that enable its seed extract to be a very effective alternative to PZQ against H. nana.