Combined Utilisation of Rapid Assessment Procedures for Loiasis (RAPLOA) and Onchocerciasis (REA) in Rain forest Villages of Cameroon

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).     

Multiple actins in drosophila melanogaster

The tissue and developmental specificities of the three Drosophila isoactins, originally identified in primary myogenic cultures and in the permanent Schneider L-2 cell line, have been investigated. Of these three isoactins (I, II, and III), actins I and II are stable and actin III is unstable. Two-dimensional polyacrylamide gel electrophoretic analyses of total cellular extracts after 1-h [(35)S]methionine pulses were performed on a large variety of embryonic, larval, and adult muscle and nonmuscle tissues. The results suggest that isoactins II and III are generalized cellular actins found in all drosophila cell types. Actin I, on the other hand, is muscle-associated and is found exclusively in supercontractile muscle (such as larval body wall and larval and adult viscera) including primary myogenic cell cultures. Although actin I synthesis is not detectable during very early embryogenesis, it is detectable by 25 h and actin I is a major stable actin in all larval muscle tissues. Actin I is synthesized in reduced amounts relative to the other actins in late third instar larvae but is again a major product of actin synthesis in the adult abdomen. A stable actin species with the same pI as actin III has been identified in the adult thorax and appears to be unique to flight muscle tissue. This new stable form of thoracic actin may be the result of a stabilization of the actin III found in other tissues or may be an entirely separate gene product.     

Babesia bovis (argentina): observations of coagulation parameters, fibrinogen catabolism and fibrinolysis in intact and splenectomized cattle

The results of this paper indicate that cattle infected with B. bovis (argentina) have a markedly altered and activated coagulation system. A degree of thrombin activation occurs due partly to release of thromboplastin-like substances from lysed erythrocytes but due primarily to activation of kallikrein by babesial proteases. This produces a hyperfibrinogenaemia, particularly in intact cattle, with soluble fibrin complexes constituting up to one-third of the total fibrinogen concentration. High molecular weight non-coagulable fibrinogen-like proteins are detected terminally but more so in splenectomized cattle. Plasminogen concentration decreases in splenectomized but not intact cattle while low molecular weight fibrinogen degradation products are not easily detected. It is suggested that a hypercoagulable intermediate state with little or no fibrin deposition occurs rather than terminal disseminated intravascular coagulation.     

Concentration of Babesia bigemina-infected erythrocytes using a dextran sulphate affinity column

Babesia bigemina-infacted erythrocytes preferentially bind to dextran sulphate affinity columns. Subsequent elution yields suspensions containing up to 95% infected erythrocytes. Preliminary immunoblotting studies indicate a parasite antigen of 35,000 mol. wt might be implicated in the binding.     

Babesia argentina: observations on the immunogenicity of the cryofibrinogen complex.

Rabbit antisera were prepared against the soluble and insoluble fractions of a cryofibrinogen complex that formed in plasma of cattle acutely infected with Babesia argentina. Analyses of the rabbit antisera indicated that the cryofibrinogen complex contained proteins from erythrocytes and parasites as well as fibrinogen and related proteins.     

A cold precipitable fibrinogen complex in the plasma of cattle dying from infection with Babesia argentina.

Plasma from cattle dying from infection with Babesia argentina formed a cold precipitable gel when stored at 4 degrees C. Immunodiffusion and electrophoresis showed the soluble phase of the gel to consist mainly of a fibrinogen-like protein with small amounts of other plasma proteins. Gel filtration and specific clotting assays demonstrated a wide molecular weight spectrum of fibrinogen-like proteins, most of which appeared to be soluble fibrin in either monomer or complex forms. The possibility that proteolytic enzymes might be responsible for the formation of the gel is discussed.