Unveiling the effects of berenil, a DNA-binding drug, on Trypanosoma cruzi: implications for kDNA ultrastructure and replication.
; ; et al
in Parasitology research (2014)
Trypanosoma cruzi, the etiological agent of Chagas disease, exhibits a single mitochondrion with an enlarged portion termed kinetoplast. This unique structure harbors the mitochondrial DNA (kDNA ... [more ▼]
Trypanosoma cruzi, the etiological agent of Chagas disease, exhibits a single mitochondrion with an enlarged portion termed kinetoplast. This unique structure harbors the mitochondrial DNA (kDNA), composed of interlocked molecules: minicircles and maxicircles. kDNA is a hallmark of kinetoplastids and for this reason constitutes a valuable target in chemotherapeutic and cell biology studies. In the present work, we analyzed the effects of berenil, a minor-groove-binding agent that acts preferentially at the kDNA, thereby affecting cell proliferation, ultrastructure, and mitochondrial activity of T. cruzi epimastigote form. Our results showed that berenil promoted a reduction on parasite growth when high concentrations were used; however, cell viability was not affected. This compound caused significant changes in kDNA arrangement, including the appearance of membrane profiles in the network and electron-lucent areas in the kinetoplast matrix, but nuclear ultrastructure was not modified. The use of the TdT technique, which specifically labels DNA, conjugated to atomic force microscopy analysis indicates that berenil prevents the minicircle decatenation of the network, thus impairing DNA replication and culminating in the appearance of dyskinetoplastic cells. Alterations in the kinetoplast network may be associated with kDNA lesions, as suggested by the quantitative PCR (qPCR) technique. Furthermore, parasites treated with berenil presented higher levels of reactive oxygen species and a slight decrease in the mitochondrial membrane potential and oxygen consumption. Taken together, our results reveal that this DNA-binding drug mainly affects kDNA topology and replication, reinforcing the idea that the kinetoplast represents a potential target for chemotherapy against trypanosomatids. [less ▲]Detailed reference viewed: 20 (2 ULg)
Identification of hard ticks (Acari: Ixodidae) and seroprevalence to Theileria parva in cattle raised in North Kivu Province, Democratic Republic of Congo.
; Saegerman, Claude ; et al
in Parasitology research (2013), 112(2), 789-97
This study aimed to identify tick species and to determine their relationship with the Theileria parva seroprevalence in cattle raised under an extensive farming system in North Kivu Province, Democratic ... [more ▼]
This study aimed to identify tick species and to determine their relationship with the Theileria parva seroprevalence in cattle raised under an extensive farming system in North Kivu Province, Democratic Republic of Congo in two agro-ecological zones namely medium (1,000-1,850 m) and high (>1,850 m) altitude. Among the 3,215 ticks collected on 482 animals, from February to April 2009, Rhipicephalus appendiculatus (64.26 %), the main vector of T. parva, was the most abundant species followed by Rhipicephalus decoloratus (35.49 %) and Amblyomma variegatum (0.25 %). The mean burden of R. appendiculatus tick per infested animal appeared significantly higher at medium (6.5 +/- 0.22 ticks) than at high (0.07 +/- 0.3 ticks) altitude (P < 0.05). However, an indirect fluorescent antibody test carried out on 450 blood samples revealed a global T. parva seroprevalence of 43 % (95 % CI: 38-47) which was not significantly (P > 0.05) different between medium (48.4 %; 95 % CI: 38-49) and high (41.9 %; 95 % CI: 35-49) altitude. These relatively low seroprevalences suggest that there is a state of endemicity to T. parva infection in the study area. The presence of the tick vector on animals was associated with an increased risk of being seropositive to T. parva infection (odds ratio = 2.04; 95 % CI: 1.8-2.3; P < 0.001). The results suggest the need for a longitudinal study to investigate the seasonal dynamics of tick species and T. parva infection. The rate of tick infection should also be evaluated in order to determine the intensity of T. parva transmission to cattle. [less ▲]Detailed reference viewed: 20 (2 ULg)
Longitudinal field study on bovine Babesia spp. and Anaplasma phagocytophilum infections during a grazing season in Belgium
Lempereur, Laetitia ; ; et al
in Parasitology Research (2012), 110(4), 1525-1530
Anaplasmosis and babesiosis are major tick-borne diseases with a high economic impact but are also a public health concern. Blood samples collected in the spring, summer, and autumn of 2010 from 65 cows ... [more ▼]
Anaplasmosis and babesiosis are major tick-borne diseases with a high economic impact but are also a public health concern. Blood samples collected in the spring, summer, and autumn of 2010 from 65 cows in seven different farms in Belgium were monitored with an indirect immunofluorescence antibody test to assess seroprevalence against these pathogens. Seroprevalences to Babesia spp. were measured as 10.7%, 20%, and 12.3% in spring, summer, and autumn, respectively, whereas seroprevalences to Anaplasma phagocytophilum were 30.8%, 77%, and 56.9%, respectively. A total of 805 Ixodes ricinus ticks were collected at the same time from both cattle (feeding ticks) and grazed pastures (questing ticks). The infection level of ticks, assessed by PCR assay, for Babesia spp. DNA was 14.6% and 7.9% in feeding and questing ticks, respectively, whereas 21.7% and 3% of feeding and questing ticks were found be positive for A. phagocytophilum cDNA. Fifty-five PCR-positive samples were identified by sequencing as Babesia sp. EU1, of which five from feeding ticks were positive for both A. phagocytophilum and Babesia sp. EU1. The high density of wild cervids in the study area could explain these observations, as deer are considered to be the main hosts for adults of I. ricinus. However, the absence of Babesia divergens both in feeding and questing ticks is surprising, as the study area is known to be endemic for cattle babesiosis. Increasing cervid populations and comorbidity could play an import role in the epidemiology of these tick-borne diseases. [less ▲]Detailed reference viewed: 82 (19 ULg)
The detection and quantification of a digenean infection in the snail host with special emphasis on Fasciola sp.
Caron, Yannick ; ; Losson, Bertrand
in Parasitology Research (2008), 103(4), 735-44
In this review, ten methods used to study digenean infections in their intermediate hosts were compared to determine which one should be used either in the field or in the lab to establish the prevalence ... [more ▼]
In this review, ten methods used to study digenean infections in their intermediate hosts were compared to determine which one should be used either in the field or in the lab to establish the prevalence and intensity of infections in snails. Snail crushing and snail dissection allow quick establishing of prevalence in natural or experimental infections, whereas histology is considered as the most accurate approach to assess the intensity of infection. The follow-up of cercarial shedding only gave an idea on cercarial production. Among recently developed techniques, polymerase chain reaction (PCR) brings the most accurate information and shows high sensitivity and specificity levels when compared to blotting techniques. The easiness and relatively low cost of the basic PCR protocol make it interesting to investigate the epidemiology of the liver fluke in a lab with limited financial resources. Nevertheless, if this technique allows a relatively good estimation of the prevalence, information concerning the intensity of infection is best obtained through real time PCR. However, at the time being this technique is too expensive to be used routinely in the field. The choice between classical or new techniques is usually based on a compromise, as each technique has its advantages and drawbacks. [less ▲]Detailed reference viewed: 39 (7 ULg)