Eichner M et al. (1990) Trop Med Parasitol "Differential length of Onchocerca volvulus infective larvae from the Cameroon rain forest and savanna."

Renz A, Eichner M

[Trop Med Parasitol, 1990]

Infective larvae from the savanna strain of Onchocerca volvulus are significantly longer (662.6 +/- 66.8 microns; n = 99) than those from the forest strain (624.2 +/- 62.0 microns; n = 236). The length of the infective larvae is not influenced by the size, species or age post infectionem (pi) of the Simulium damnosum s. l. vectors nor by their localization in the fly's head, thorax or abdomen, the worm load per fly or the thoracic volume per larva. However, the lengths of infective larvae within one individual fly have a conspiciously low variance.

Wanji S et al. (2005) Filaria J "Combined Utilisation of Rapid Assessment Procedures for Loiasis (RAPLOA) and Onchocerciasis (REA) in Rain forest Villages of Cameroon."

Enyong P, Tendongfor N, Wanji S, Esum M, Taylor MJ, Yundze SS

[Filaria J, 2005]

BACKGROUND: Individuals with high microfilarial loads of Loa loa are at increased risk of neurologic serious adverse (SAE) events following ivermectin treatment against onchocerciasis. RAPLOA (Rapid Assessment Procedure for loiasis), a newly developed rapid assessment procedure for loiasis that relates the prevalence of key clinical manifestation of loiasis (history of eye worm) to the level of endemicity of the infection (prevalence of high intensity), is a very useful tool to identify areas at potential risk of L. loa post ivermectin treatment encephalopathy. In a perspective of treatment decision making in areas of co-endemicity of loiasis/onchocerciasis, it would be advantageous (both in time and cost savings) for national onchocerciasis control programmes to use RAPLOA and the Rapid epidemiologic assessment for onchocerciasis (REA), in combination in given surveys. Since each of the two rapid assessment tools have their own specificities, the workability of combining the two methods needed to be tested. METHODS: We worked in 10 communities of a forest area presumed co-endemic for loiasis and onchocerciasis in the North-West Province of Cameroon where the mass-treatment with ivermectin had not been carried out. A four-step approach was used and comprised: (i) generating data on the prevalence and intensity of loiasis and onchocerciasis in an area where such information is scarce; (ii) testing the relationship between the L. loa microfilaraemia prevalence and the RAPLOA prevalence, (iii) testing the relationship between the O. volvulus microfiladermia prevalence and the REA prevalence, (iv) testing the workability of combining RAPLOA/REA by study teams in which a single individual can perform the interview for RAPLOA and the nodule palpation for REA. RESULTS: The microfilaraemia prevalence of loiasis in communities ranged from 3.6% to 14.3%. 6 (0.61%) individuals had L. loa microfilarial loads above 8000 mf/ml but none of them attained 30,000 mf/ml, the threshold value above which the risk of developing neurologic SAE after ivermectin treatment is very high. None of the communities surveyed had RAPLOA prevalence above 40%. All the communities had microfiladermia prevalence above 60%. The microfiladermia results could be confirmed by the rapid epidemiologic method (nodule palpation), with all the 10 communities having REA prevalence above 20%. For the first time, this study has demonstrated that the two rapid assessment procedures for loiasis and onchocerciasis can be carried out simultaneously by a survey team, in which a single individual can administer the questionnaire for RAPLOA and perform the nodule palpation for REA. CONCLUSION: This study has: (i) Revealed that the Momo valley of the North West province of Cameroon is hyperendemic for onchocerciasis, but is of lower level of endemicity for L. loa. (ii) Confirmed the previous relationships established between RAPLOA and the L. loa microfilaraemia prevalence in one hand and between the REA and the O. volvulus microfiladermia prevalence in another hand (iii) Shown that RAPLOA and REA could be used simultaneously for the evaluation of loiasis and onchocerciasis endemicity in areas targeted by the African Programme for onchocerciasis Control for community-directed treatment with ivermectin (CDTI).

Garms R (1987) Trop Med Parasitol "Infection rates and parasitic loads of Onchocerca volvulus, and other filariae, in Simulium sanctipauli s.l. and S. yahense in a rain-forest area of Liberia."

Garms R

[Trop Med Parasitol, 1987]

Simulium sanctipauli s.l. and S. yahense are common and widespread in the rain-forest zone of Liberia, but differ with regard to their biting densities and contribution to the transmission of Onchocerca volvulus. Although, in a study area on the St. Pauli River, S. sanctipauli s.l. (presumably S. soubrense in the sense of Post) was the predominant ma-biting species (74.3% of 30,855 females examined), S. yahense was shown to be the important vector. While 1000 biting females of S. yahense carried 96 3rd stage larvae indistinguishable from O. volvulus, only 14 were found per 1000 females of S. sanctipauli s.l. Of the parous females (3135 S. sanctipauli s.l./1621 S. yahense) 23.8/39.9% harboured 1st and/or 2nd stage filarial larvae and 1.9/9.4% 3rd stage larvae of O. volvulus. Animal filariae of unknown origin, indicative of zoophily, were very common in S. sanctipauli s.l. (13.8%) but practically absent from S. yahense (0.5%). In spite of its poorer vectorial performance S. sanctipauli s.l. cannot be neglected as a vector because it may occur in high biting densities and contribute considerably to the transmission, in particular in the vicinity of the St. Paul River. The interplay of two vector species, which develop in different types of water-courses explains the overall high endemicity of onchocerciasis in the study area.

Omar MS et al. (1982) Bull World Health Organ "Histochemical enzyme variation in Onchocerca volvulus microfilariae from rain-forest and Sudan-savanna areas of the Onchocerciasis Control Programme in West Africa."

Marshall TF, Omar MS, Prost A

[Bull World Health Organ, 1982]

Histochemical staining methods for acid phosphatase were used to study the differences among microfilariae of various West African strains of Onchocerca volvulus in both forest and Sudan-savanna onchocerciasis zones. The results have shown statistically significant differences in the staining patterns of microfilarial populations in the two zones. In the rain-forest areas, where onchocerciasis is transmitted by Simulium yahense, S. sanctipauli, S. soubrense and S. squamosum, there were no significant differences of microfilarial staining patterns in patients, by age and sex, between the three Simulium-Onchocerca complexes studied. There was a close relationship between the "strain differences", as revealed morphoenzymatically, and the clinical picture of the disease in both the forest and the Sudan-savanna zones. The present findings are in favour of the hypothesis that there are intrinsic differences in the strains of the parasite occurring in the two areas. The application of the histochemical means of parasite characterization appears to be a useful tool in differentiating strains of O. volvulus and could contribute towards a better understanding of the epidemiology of human onchocerciasis in different bioclimatic zones where the disease is endemic.

Garms R (1985) Trop Med Parasitol "Morphological differentiation from Onchocerca volvulus of first stage larvae of an unknown filarial species commonly found in Simulium sanctipauli s.l. in Liberia."

Garms R

[Trop Med Parasitol, 1985]

A filarial species of unknown origin was frequently found in Simulium sanctipauli s.l. in the rain-forest zone of Liberia. After staining the cephalic armature with alcian blue its first stage larvae could be easily distinguished from those of Onchocerca volvulus.

Traore S et al. (1997) Bull Soc Pathol Exot "[Natural vector capacity level of Simulium damnosum s.l. (Diptera: Simuliidae) at the ecology station of Tai (Cote d'Ivoire)]."

Hebrard G, Riviere F, Diarrassouba S, Traore S

[Bull Soc Pathol Exot, 1997]

Several studies have been carried out on the transmission of Onchocerciasis by Simulium damnosum s.l. in the forest zone of Cote d'Ivoire. This study, carried out in 1979-1980 was devoted to determine the risk of onchocerciasis transmission inside and outside the rain forest of Tai (5 degrees 50' N-7 degrees 25' W). We present the vectorial capacity of S. sanctipauli in the region of Tai before massive flow of refugees from areas of Liberia without any control Programme. The results of micromorphological technics for determination of S. damnosum adults, showed that mainly females of S. sanctipauli were present. The studied populations had low parturity rates: 39.2% outside and 30.9% of parous flies inside the rain forest. The parasitic rates (0.4% of infectious females outside and 0.1% inside) and their parasitic loads (15 and 3 infective larvae per 1000 parous female respectively outside and inside the rain forest) were low, consequently their vectorial capacity with Onchocerca volvulus was almost non-existent in natural conditions. Before massive flow of refugees including persons carrying microfilariae, there were no problem of onchocerciasis within and outside the rain forest of Tai. However, the massive flow of refugees and the deforestation for growing crops can create situations favourable to the installation of more efficient vectors, increase man/vector contact and contribute to more intense onchocerciasis transmission. The monitoring of onchocerciasis transmission is necessary.

Cupp EW et al. (1986) Science "The effects of ivermectin on transmission of Onchocerca volvulus."

Cupp EW, Kiszewski AE, Collins RC, Greene BM, Aziz MA, Taylor HR, Bernardo MJ

[Science, 1986]

Ivermectin, given to onchocerciasis patients as a single oral dose of 200 micrograms per kilogram of body weight, substantially reduced the uptake of Onchocerca volvulus microfilariae by Simulium yahense, an efficient black fly vector of the parasite in the tropical rain forests of West Africa. Three months after treatment, patients given ivermectin infected flies at a significantly lower rate than those who had received diethylcarbamazine or placebo, thereby reducing the number of developing larvae in the vector population. This diminished rate of infectiousness was also evident 6 months after treatment. These results strongly suggest that ivermectin could be effective in interrupting transmission of Onchocerca volvulus for epidemiologically important periods of time.

Caveness FE et al. (1970) J Nematol "Nematode electrocution."

Caveness CE, Caveness FE

[J Nematol, 1970]

The effects of electric shock on Panagrellus redivivus adults and larvae and Meloidogyne incognita acrita larvae were studied. The nematodes were placed in tap water between two stainless steel electrodes, spaced 2 mm apart and cemented to a glass slide. Electric potentials of 1, 5, 10, 15, 20, 30, and 60 vdc/mm and vac/mm were applied for periods of 1 sec to 5 rain at 0.05 to 77 ma. The results demonstrated that ac or dc electric shocks as low as 5 v/mm for larvae and 10 v/mm for adults can be lethal. Some larvae and eggs within the body of P. redivivus females were not affected at 600 v/ram. Potentials of 20 and 60 vdc/mm for 2-sec stimulated hatch of Meloidogyne eggs.

Xiao J et al. (2013) Proc Natl Acad Sci U S A "Crystal structure of the Golgi casein kinase."

Wen J, Kim SA, Dixon JE, Tagliabracci VS, Xiao J

[Proc Natl Acad Sci U S A, 2013]

The family with sequence similarity 20 (Fam20) kinases phosphorylate extracellular substrates and play important roles in biomineralization. Fam20C is the Golgi casein kinase that phosphorylates secretory pathway proteins within Ser-x-Glu/pSer motifs. Mutations in Fam20C cause Raine syndrome, an osteosclerotic bone dysplasia. Here we report the crystal structure of the Fam20C ortholog from Caenorhabditis elegans. The nucleotide-free and Mn/ADP-bound structures unveil an atypical protein kinase-like fold and highlight residues critical for activity. The position of the regulatory C helix and the lack of an activation loop indicate an architecture primed for efficient catalysis. Furthermore, several distinct elements, including the presence of disulfide bonds, suggest that the Fam20 family diverged early in the evolution of the protein kinase superfamily. Our results reinforce the structural diversity of protein kinases and have important implications for patients with disorders of biomineralization.

Petersen C et al. (2014) BMC Ecol "The prevalence of Caenorhabditis elegans across 1.5years in selected North German locations: the importance of substrate type, abiotic parameters, and Caenorhabditis competitors."

Dirksen P, Petersen C, Schulenburg H, Strathmann EA, Prahl S

[BMC Ecol, 2014]

BACKGROUND: Although the nematode Caenorhabditis elegans is a major model organism in diverse biological areas and well studied under laboratory conditions, little is known about its ecology. Therefore, characterization of the species' natural habitats should provide a new perspective on its otherwise well-studied biology. The currently best characterized populations are in France, demonstrating that C. elegans prefers nutrient- and microorganism-rich substrates such as rotting fruits and decomposing plant matter. In order to extend these findings, we sampled C. elegans continuously across 1.5years from rotting apples and compost heaps in three North German locations. RESULTS: C. elegans was found throughout summer and autumn in both years. It shares its habitat with the related nematode species C. remanei, which could thus represent an important competitor for a similar ecological niche. The two species were isolated from the same site, but rarely the same substrate sample. In fact, C. elegans was mainly found on compost and C. remanei on rotten apples, possibly suggesting niche separation. The occurrence of C. elegans itself was related to environmental humidity and rain, although the correlation was significant for only one sampling site each. Additional associations between nematode prevalence and abiotic parameters could not be established. CONCLUSIONS: Taken together, our findings vary from the previous results for French C. elegans populations in that the considered German populations always coexisted with the congeneric species C. remanei (rather than C. briggsae as in France) and that C. elegans prevalence can associate with humidity and rain (rather than temperature, as suggested for French populations). Consideration of additional locations and time points is thus essential for full appreciation of the nematode's natural ecology.