A marked seasonality of malaria transmission in two rural sites in eastern Sudan

The ecology of Anopheles arabiensis and its relationship to malaria transmission was investigated in two villages in eastern Sudan. Seasonal malaria case incidence was compared with the number of vectors detected and with climatic variables. Following the end of the short rainy season in October the number of A. arabiensis detected dropped gradually until February when neither outdoor human bait trapping nor indoor spray catches revealed any mosquitoes. Vectors re-appeared in June as humidity rose with the onset of rain. Despite the apparent absence of the vector at the height of the long, hot dry season between February and May, sporadic asymptomatic malaria infections were detected in the two villages. The low endemicity of malaria in the area was reflected by the relatively low total September-December parasite and sporozoite rates (15 and 1.4%, respectively) measured in the villages. The entomological inoculation rate (EIR) was estimated to be around two to three infective bites per person per year, although heterogeneity in the transmission indices of malaria between the two villages was observed. The implications of these patterns of anopheline population dynamics for the epidemiology and control of malaria in eastern Sudan are considered.     

Efficacy of four insect repellents against mosquito bites: a double-blind randomized placebo-controlled field study in Senegal

Insect-borne diseases represent a worldwide threat. In addition to fight against vectors (insecticides) and disease prevention (vaccination against yellow fever, chemoprophylaxis against malaria), insect repellents applied on the skin could help reduce the heavy burden related to these diseases. In a field study performed in Senegal, we compared the efficacy of one skin application between 3 and 4 p.m. of four spray repellents [icaridine 20%, para-menthane-diol (PMD) 20% and 50% and DEET 50%] against placebo, among 100 healthy male and female volunteers experienced with mosquito capture. Double-blind randomized cross-over placebo-controlled study (Latin-square design) during five consecutive nights (7 p.m. to midnight) in two villages was conducted. To avoid residual effect, right or left leg was alternately exposed during consecutive nights and the exposed leg was washed before next night. The statistical model was random and mixed effects anova . All four active repellents provided a significant and similar protection compared with placebo, lasting 8 h. However, there was a non-significant trend for a higher protection by DEET 50% than by PMD 20% ( P  = 0.07). Duration of protection was similar for all repellents. Their effects were similar among men and women, and against Anopheles or other species. No serious adverse drug reaction was noticed. Using a rigorous methodology and a large number of volunteers, our well-controlled study demonstrated an important and similar protective effect of all four repellents compared with placebo. Such field studies should be required before approval of any newly developed repellent.     

Emergence and course of the ilioinguinal nerve of the groin

The aim of our study was to find a way of preserving the ilioinguinal nerve during surgical procedures for the repair of inguinal hernias. 40 inguinal regions were dissected, 37 ilio-inguinal nerves studied. The emergence of the nerve was at 4.21 cm of the anterior superior iliac spine, at 0.78 cm of the inguinal ligament on average. Its course was parallel to the inguinal ligament, always lay under the aponevrosis of the external oblique abdominal muscle, it passed through the superficial abdominal ring in 67.56% before proceeding on anterior side of spermatic cord. This result allowed us to examine the possibility of the nerve course variation's, of anastomosis with iliohypogastric nerve and particularly the best way to identify it when surgical procedures are performed in the lower portion of the abdomen.     

Impact of mosquito bites on asexual parasite density and gametocyte prevalence in asymptomatic chronic Plasmodium falciparum infections and correlation with IgE and IgG titers

An immunomodulatory role of arthropod saliva has been well documented, but evidence for an effect on Plasmodium sp. infectiousness remains controversial. Mosquito saliva may orient the immune response toward a Th2 profile, thereby priming a Th2 response against subsequent antigens, including Plasmodium. Orientation toward a Th1 versus a Th2 profile promotes IgG and IgE proliferation, respectively, where the former is crucial for the development of an efficient antiparasite immune response. Here we assessed the direct effect of mosquito bites on the density of Plasmodium falciparum asexual parasites and the prevalence of gametocytes in chronic, asymptomatic infections in a longitudinal cohort study of seasonal transmission. We additionally correlated these parasitological measures with IgE and IgG antiparasite and anti-salivary gland extract titers. The mosquito biting density was positively correlated with the asexual parasite density but not asexual parasite prevalence and was negatively correlated with gametocyte prevalence. Individual anti-salivary gland IgE titers were also negatively correlated with gametocyte carriage and were strongly positively correlated with antiparasite IgE titers, consistent with the hypothesis that mosquito bites predispose individuals to develop an IgE antiparasite response. We provide evidence that mosquito bites have an impact on asymptomatic infections and differentially so for the production of asexual and sexual parasites. An increased research focus on the immunological impact of mosquito bites during asymptomatic infections is warranted, to establish whether strategies targeting the immune response to saliva can reduce the duration of infection and the onward transmission of the parasite.     

Uterine torsion with maternal death: our experience and literature review

Torsion of the gravid uterus around its cervical junction is a rare event especially in humans. In 1992, a literature review by Jensen, mentioned by Carbonne, showed 212 cases with different etiologies. Uterine torsion is more frequently dextrorotatory (2/3 of cases). The diagnosis is difficult and generally done during cesarean section because it is frequently not symptomatic. Uterine torsion signs, when present, are not specifics. Pain, nausea and vomiting may present without any sign of shock, as in our patient. Sometimes ultrasonography can lead to a correct diagnosis, showing a modification of the placenta site during pregnancy, or an abnormal positioning of the ovarian vessels which pass in front of the lower uterine segment. Some authors report cardiotocographic abnormalities probably due to the reduction of blood flow caused by the torsion. Quickness of surgical treatment is fundamental for the reduction of fetal mortality which is very frequent in a large number of cases, while maternal mortality is not so frequent but possible. A diligent anamnesis and ultrasonographic examination are surely useful to single out the rare cases of uterine torsion in pregnancy.