The In Vitro Effects of Aqueous and Ethanolic Extracts of the Leaves of Ageratum conyzoides (Asteraceae) on Three Life Cycle Stages of the Parasitic Nematode Heligmosomoides bakeri (Nematoda: Heligmosomatidae)

A comparative in vitro study was carried out to determine the ovicidal and larvicidal activity of aqueous and ethanolic extracts of Ageratum conyzoides (Asteraceae) leaves on the eggs (unembryonated and embryonated), first and second larval stages of Heligmosomoides bakeri. Four different concentrations (0.625, 1.25, 2.5, and 3.75 mg·mL−1) of both aqueous and ethanolic extracts were tested. Distilled water and 5% tween were used as negative controls in the bioassay. In fact, they did not affect development of eggs, hatching, and larval survival. The extract activities were dose dependent. The ethanolic extract was more potent against embryonation (39.6 ± 2.9%) than the aqueous extract (53.3 ± 10.9%) at the highest concentration (3.75 mg·ml−1). Both types of extracts killed larvae. Mebendazole proved more lethal (EC50 of 0.745 and 0.323 mg·mL−1, resp., for L1 and L2 larvae). The aqueous extracts were the least lethal (EC50 of 4.76 and 2.29 mg·mL−1, resp., for L1 and L2 larvae). The ethanolic extracts showed intermediate activity (EC50 of 1.323 and 1.511 mg·mL−1, resp., for L1 and L2 larvae). It is concluded that the ovicidal and larvicidal properties of aqueous and ethanolic extracts of Ageratum conyzoides leaves are demonstrated in this work

Alloantibodies, Anti-D, Childbearing age, Women, Cameroon

We conducted a cross sectional retrospective study to determine anti-D and D-negative phenotype rates among Cameroonian women of reproductive age (15 – 44 years), in order to evaluate the importance ofD alloimmunization. Analysis of the haematology laboratory records from January 2006 to December 2007 harvested 225 results for red blood cell alloantibody screening and 2460 D phenotypes. Anti-D rate was found to be high at 4% and not linked to women’s parity. Three hundred and fifty two (14.3%) women were found to be D-negative. Anti-D rates significantly decreased with age from 18.8% among teenagers (15-19) to 7.8% among older women (35-44) (p = 0.001). The number of women submitted to both irregular antibody screening and type D phenotype determination was not strong enough (50) to analyse the link between anti-D rate and antigen D distribution in our study (Afr J Reprod Health 2009; 13[3]:47-52)

Hemipyrellia fernandica (Macquart, 1855) and Hemipyrellia sp. (Print)

Abstract Carcasses of laboratory-bred red rats (Rattus rattus, Berkenhout, 1769 var Wistar) were exposed in wooden cages on the campus of the University of Yaounde I (Cameroon) to take a census and identify insects of forensic importance. Amongst the 1613 insects obtained from the emergence of maggots reared in the laboratory under ambient air temperature, the family Calliphoridae (Diptera) represents 72% (1161). The species were distributed betwee

Публицистика Джафера Сейдамета в период эмиграции (1918-1960 гг.)

Background: Parasite switches to new host species are of fundamental scientific interest and may be considered an important speciation mechanism. For numerous monogenean fish parasites, infecting different hosts is associated with morphological adaptations, in particular of the attachment organ (haptor). However, haptoral morphology in Cichlidogyrus spp. (Monogenea, Dactylogyridea), parasites of African cichlids, has been mainly linked to phylogenetic rather than to host constraints. Here we determined the position of Cichlidogyrus amieti, a parasite of species of Aphyosemion (Cyprinodontiformes, Nothobranchiidae) in the phylogeny of its congeners in order to infer its origin and assess the morphological changes associated with host-switching events. Methods: The DNA of specimens of C. amieti isolated from Aphyosemion cameronense in Cameroon was sequenced and analyzed together with that of Cichlidogyrus spp. from cichlid hosts. In order to highlight the influence of the lateral transfer of C. amieti on the haptoral sclerotised parts we performed a Principal Component Analysis (PCA) to compare the attachment organ structure of C. amieti to that of congeners infecting cichlids. Results: Cichlidogyrus amieti was found to be nested within a strongly supported clade of species described from Hemichromis spp. (i.e. C. longicirrus and C. dracolemma). This clade is located at a derived position of the tree, suggesting that C. amieti transferred from cichlids to Cyprinodontiformes and not inversely. The morphological similarity between features of their copulatory organs suggested that C. amieti shares a recent ancestor with C. dracolemma. It also indicates that in this case, these organs do not seem subjected to strong divergent selection pressure. On the other hand, there are substantial differences in haptoral morphology between C. amieti and all of its closely related congeners described from Hemichromis spp.. Conclusions: Our study provides new evidence supporting the hypothesis of the adaptive nature of haptor morphology. It demonstrates this adaptive component for the first time within Cichlidogyrus, the attachment organs of which were usually considered to be mainly phylogenetically constrained

Visual cues from different trap colours affect catches of Sahlbergella singularis (Hemiptera: Miridae) in sex pheromone traps in Cameroon cocoa plantations

Cocoa mirids, Sahlbergella singularis and Distantiella theobroma, are the most economically important insect pests of cocoa in West and Central Africa, where they can cause up to 40% losses in cocoa yields. Sahlbergella singularis is the most common species in Cameroon and was therefore targeted in this study. During a two-year trial in 15 cocoa plantations in Ayos and Konye, in the Centre and Southwest regions of Cameroon respectively, the most effective colour – white, purple or green – of sex pheromone traps was examined for integration into mirid management programmes. Similar temporal patterns in S. sahlbergella male trap catches were observed with all three colours, but the green trap caught more S. singularis (Ayos: 0.968 ± 0.091 [SEM]; Konye: 0.640 ± 0.076/trap/month) compared with purple traps (Ayos: 0.674 ± 0.068; Konye: 0.441 ± 0.058), and white traps (Ayos: 0.467 ± 0.049, Konye: 0.253 ± 0.041). Trap reflectance showed wavelength peaks typical for purple in both short (approximately 380 - 480 nm) and long wavelengths (> 650 nm), and ~530 nm for green. Reflectance peaks exceeded 100% of the incident light in the 400-450 nm range from the white, suggesting the presence of optical brighteners. Trap catches support the hypothesis that S. singularis ocelli are more responsive to light of shorter wavelengths. Despite the low attractiveness of the sex pheromone to S. singularis, a optimisation of the colour of the trap can improve S. sahlbergella monitoring, mass trapping, and other control measures which could ultimately lead to reductions of insecticide use and to conservation of beneficial arthropods, particularly cocoa flower pollinators that are critical for improving cacao tree productivity

Distribution of Gill Parasites of the Freshwater Fish <em>Barbus martorelli</em> Roman, 1971 (Teleostei: Cyprinidae) and Tendency to Inverse Intensity Evolution Between Myxosporidia and Monogenea as a function of the Host Age

The study of gill parasite fauna from 558 Barbus martorelli in a tropical freshwater course near Yaounde (Cameroon) was undertaken to collect data on the distribution of pathogens in a wild population, which is essential to find means of avoiding catastrophic losses often observed in intensive aquaculture. The analysis revealed the presence of two myxosporidian species (Myxobolus barbi and M. njinei) and eight monogenean species (Dactylogyrus bopeleti, D. insolitus, D. simplex, D. maillardi, Dogielius martorellii, Dogielius sp., one species of Gyrodactylidae and one larva of Polystomatidae). Four individual fish were found without parasites, whereas 24 and 530 presented monospecific and multispecific infections, respectively. Each infested host harbored an average of four parasite species. As the prevalence and mean intensity reduced with the host size for protozoans, the reverse phenomenon was observed for helminths. A sexual effect was observed on the infestation of B. martorelli by the myxosporidian M. njinei and by most monogenean species; females were thus more infested than males due to the biology of gravid specimens. Finally, the high parasite species richness appeared to reduce the host weight

Biotope des extoparasties branchiaux de Clarias camerunensis Lonnberg, 1895 (Pisces; clariidae): modeles de croissance de l\'aire colonisable

No Abstract. JCAS Vol. 7 (1) 2007: pp. 11-1

Monogènes parasites de Clariidae (Teleostei, Siluriformes) au Cameroun : I. Description de deux nouvelles espèces du genre Gyrodactylus dans le bassin du Nyong

L’étude des parasites branchiaux et cutanés de trois espèces de Poissons du genre Clarias : C. camerunensis, C. jaensis et C. pachynema pêchés dans le bassin du Nyong (Cameroun) a révélé la présence de deux espèces nouvelles de Monogènes du genre Gyrodactylus Nordmann : G. camerunensis n. sp. et G. nyongensis n. sp parasites de Clarias camerunensis, C. jaensis et C. pachynema. Gyrodactylus camerunensis n. sp. se sépare aisément de G. nyongensis n. sp. par la taille plus faible des pièces sclérifiées du hapteur. Ces deux nouvelles espèces se distinguent aussi des Gyrodactylus africains les plus proches, G. rysavyi, G. clarii et G. alberti par la morphologie et la taille des sclérites du hapteur. L’étude de leur spécificité montre qu’elle est du type stenoxène (mesosténoxène)

Monogènes parasites de Clariidae (Teleostei, Siluriformes) au Cameroun : I. Description de deux nouvelles espèces du genre

L’étude des parasites branchiaux et cutanés de trois espèces de Poissons du genre Clarias : C. camerunensis, C. jaensis et C. pachynema pêchés dans le bassin du Nyong (Cameroun) a révélé la présence de deux espèces nouvelles de Monogènes du genre Gyrodactylus Nordmann : G. camerunensis n. sp. et G. nyongensis n. sp parasites de Clarias camerunensis, C. jaensis et C. pachynema. Gyrodactylus camerunensis n. sp. se sépare aisément de G. nyongensis n. sp. par la taille plus faible des pièces sclérifiées du hapteur. Ces deux nouvelles espèces se distinguent aussi des Gyrodactylus africains les plus proches, G. rysavyi, G. clarii et G. alberti par la morphologie et la taille des sclérites du hapteur. L’étude de leur spécificité montre qu’elle est du type stenoxène (mesosténoxène)