Chikungunya virus infection prevalence in Africa: a contemporaneous systematic review and meta-analysis.

OBJECTIVES: The (re)emergence of chikungunya virus (CHIKV) in Africa requires better knowledge on the epidemiology of CHIKV infection in the continent for efficient public health strategies. We aimed to describe the epidemiology of CHIKV infection in Africa, a neglected tropical disease (NTD). STUDY DESIGN: This was a systematic review with meta-analysis of studies reporting CHIKV infection prevalence. We searched Embase, PubMed, Africa Journal Online and Global Index Medicus to identify observational studies published from January 2000 to September 2017. METHODS: We used a random-effect model to pool the prevalence of CHIKV infections reported with their 95% confidence interval (CI). Heterogeneity was assessed via the Chi-squared test on Cochran's Q statistic. Review registration is in PROSPERO CRD42017080395. RESULTS: A total of 39 studies (37,881 participants; 18 countries) were included. No study was reported from Southern Africa. Thirty-two (82.0%), seven (18.0%) and no studies had low, moderate and high risk of bias, respectively. Outside outbreak periods, the pooled immunoglobulin M (IgM) and immunoglobulin G (IgG) seroprevalence was 9.7% (95% CI 3.0-19.6; 16 studies) and 16.4% (95% CI 9.1-25.2; 23 studies), respectively. The IgM seroprevalence was lower in Northern Africa, and there was no difference for IgG prevalence across regions in Africa. The IgM and IgG seroprevalences were not different between acute and non-acute febrile participants. The seroprevalence was not associated with GPS coordinates (latitude, longitude and altitude). CONCLUSIONS: Although considered a NTD, we find high prevalence of CHIKV infection in Africa. As such, chikungunya fever should deserve more attention from healthcare providers, researchers, policymakers and stakeholders from many sectors.

Anti-inflammatory, antimicrobial and antioxidant activities of Diospyros bipindensis (Gürke) extracts and its main constituents.

ETHNOPHARMACOLOGICAL RELEVANCE: Diospyros bipindensis (Gürke) stem bark is used in Cameroon by Baka Pygmies for the treatment of respiratory disorders. AIM OF THE STUDY: To assess the anti-inflammatory, antibacterial and antioxidant properties of constituents from the bark extracts through bioassay-guided fractionation. MATERIALS AND METHODS: The anti-inflammatory activity of extracts, fractions and pure compounds was assessed through the inhibition of the pro-inflammatory mediator nuclear factor-kappa B (NF-κB) transcriptional activity and nitric oxide (NO) production. DPPH, ABTS and ORAC assays were used for determining the antioxidant properties. The activity against Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Klebsiella pneumoniae, was evaluated on the basis of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) by the macrodilution method. RESULTS: The water extract showed antimicrobial activity against S. pneumoniae (MIC: 300 µg/ml) and S. pyogenes (MIC: 300 µg/ml). The dichloromethane extract efficiently inhibited NF-κB transcriptional activity and NO production and exhibited significant antioxidant activity in the ORAC assay. An interesting activity was also found against S. pneumoniae (MIC: 200 µg/ml), S. aureus (MIC: 400 µg/ml) and S. pyogenes (MIC: 200 µg/ml). The phytochemical investigation of the dichloromethane extract afforded plumbagin, canaliculatin, ismailin, betulinic acid and 4-hydroxy-5-methyl-coumarin as the main constituents. Plumbagin and ismailin were found to be responsible for the main biological activities observed. CONCLUSIONS: These results may provide a rational support for the traditional use of Diospyros bipindensis stem bark in the treatment of respiratory disorders, since the anti-inflammatory, antimicrobial and antioxidant compounds isolated from the dichloromethane extract were also present in the traditional water extract.

Effect of methanol extract of Basella alba L. (Basellaceae) on the fecundity and testosterone level in male rats exposed to flutamide in utero.

We evaluated the effect of the methanol extract of Basella alba (MEBa) on testosterone level and fecundity/fertility in male rats exposed in utero to flutamide - an androgen receptor antagonist. For this purpose, 1.5- and 2.5 -month-old male rats exposed in utero to flutamide were treated with the MEBa (1 mg kg(-1) ) for 2 and 1 month respectively. Five days before the end of treatment, rats were housed with females to assess their fecundity/fertility. Thereafter, rats were sacrificed and blood collected for the quantification of testosterone. Flutamide-exposed male rats showed a decrease in their ano-genital distance (AGD, P < 0.05) and were infertile. In normal (methylcellulose-exposed) animals, MEBa provoked an increase in testosterone level in 1.5- (P < 0.008) and 2.5 -month-old rats (P < 0.01) concomitantly with the improvement in their fecundity by 25%. In flutamide-exposed male rats, MEBa increased testosterone level in 1.5 -month-old rats (P < 0.001) without any effect on their fecundity; while in 2.5- month-old rats, MEBa did not affect the testosterone level but improved fecundity (by 25%) and fertility (P < 0.001). This study demonstrated the positive effect of MEBa to enhance fecundity/fertility in normal male rats and in rats exposed to the antiandrogen flutamide during their foetal life.

Inductive effect of the leaf mixture extract of Aloe buettneri, Justicia insularis, Dicliptera verticillata and Hibiscus macranthus on in vitro production of estradiol.

In the course of a preliminary clarification of the mechanisms of the leaf mixture extract of Aloe buettneri, Justicia insularis, Dicliptera verticillata and Hibiscus macranthus, locally used to regulate the menstrual cycle and to treat dysmenorrhea or cases of infertility in women, pieces of proestrus rat ovary were incubated in the presence of increasing concentration of the plant extract and/or human Chorionic Gonadotropin (hCG). The in vitro production of estradiol and progesterone by ovarian cells of proestrus rat was significantly increased in the presence of various concentration of hCG (P < 0.05). The different concentration of the plant extract increased the production of estradiol by twofold. In addition, the in vitro production of estradiol by ovarian cells increased by 13-fold when they were incubated with hCG (0.1 IU/ml) and a concentration of 130 microg/ml of the plant extract. These results clearly attest the direct effects of some chemical components of the leaf mixture of the plants on ovarian steroidogenesis.

Oestrogenicity and effect on hepatic metabolism of the aqueous extract of the leaf mixture of Aloe buettneri, Dicliptera verticillata, Hibiscus macranthus and Justicia insularis.

The aqueous extract of the leaf mixtures of Aloe buettneri, Dicliptera verticillata, Hibiscus macranthus and Justicia insularis given by oral route to immature female rats, at doses of 13, 49 and 94 mg/kg per day for 15 days induced a significant increase in ovarian and uteri weight as well as serum and ovarian oestradiol. Moreover, a significant decrease in liver of aminopyrine N-demethylase activity was noticed in treated animals.

Reversible antispermatogenic and antifertility activities of Mondia whitei L. in male albino rat.

Chronic administration of Mondia whitei L. root bark extract (400 mg/kg/day) for 55 days caused testicular lesions resulting in the cessation of spermatogenesis, degenerative changes in the seminiferous tubules and epididymides. The wet weight of the seminal vesicle increased, whereas the weights of testes, epididymides and ventral prostate were unchanged. The treatment also resulted in a partial antifertility effect, and an increase in the protein content of the testes and epididymides. The cholesterol contents of the testes were significantly elevated after 55 days, whereas testosterone and 17beta-oestradiol contents of the testes were unchanged. Serum protein was elevated but serum testosterone was unchanged. A recovery period resulted in normal spermatogenesis and fertility, suggesting reversible antispermatogenic and antifertility effects of the plant.

Protective role of Anacardium occidentale extract against streptozotocin-induced diabetes in rats.

The protective effect of Anacardium occidentale aqueous extract against streptozotocin-induced diabetes was evaluated in rats. The rats were treated with 175 mg/kg of the extract per os, twice daily; beginning 2 days before streptozotocin (STZ) injection. A total of 3 days after STZ administration, there was a 48% increase in blood glucose level in pretreated rats, compared with a 208% increase in diabetic control rats treated with STZ alone. Furthermore, these pretreated animals presented no glycosuria, a normal weight gain and a non significant increase in food and fluid intake at the end of the treatment compared with the normal control. Diabetic control animals showed a positive glycosuria, body weight loss, a real polyphagia and polydypsia. These results indicate the protective role of Anacardium occidentale extract against the diabetogenic action of STZ.

Effects of an aqueous extract of Aloe buettneri, Justicia insularis, Hibiscus macranthus, Dicliptera verticillata on some physiological and biochemical parameters of reproduction in immature female rats.

Different doses of aqueous extracts from the leaves of Aloe buettneri, Justicia insularis, Hibiscus macranthus and Dicliptera verticillata, locally used to regulate the menstrual cycle and to treat dysmenorrhea or infertility in women, were given daily to 22 day old rats for 5, 10, 15, 20 and 25 days by gastric intubation. At the end of each experimental period, the weights of ovaries and uteri, levels of uterine and ovarian proteins, ovarian cholesterol and serum oestradiol were evaluated. The results showed a decrease in growth rate of animals treated with 94 mg/kg per day at the end of the experimental period. The ovarian and uterine weights were high in all treated groups especially within the pubertal period (36-41 days old) when compared to the respective controls. During the same period, the parameters analysed showed significant differences in treated rats when compared to the controls. This was seen with ovarian and uterine protein levels, as well as with serum oestradiol whose level was especially high in the groups given 49 or 94 mg/kg per day of the plant extracts (52 and 42%, respectively when compared with the respective controls). A concomitant decrease in ovarian cholesterol was observed in the same treated groups. These results suggested a possible presence of oestrogenic compounds in the plant extracts.

Effect of the leafy vegetable Solanum nigrum on the activities of some liver drug-metabolizing enzymes after aflatoxin B1 treatment in female rats.

Wistar albino female rats were maintained for 10 d on diets containing various levels of the vegetable Solanum nigrum. Simultaneously, they received daily intraperitoneal injections of aflatoxin B1 (AFB1) (either 0.2 or 0.4 mg/kg body-weight) diluted in propylene glycol. At the end of the experiment, all animals were killed and their serum and hepatic microsomes were prepared for assay of enzymes. Results showed that aminopyrine N-demethylase activity increased 2.5-fold with 200 (S200) and 600 (S600) g S. nigrum/kg diets. Activity of uridine diphosphate glucuronyltransferase (UDPGT) (EC 2.4.1.17) also increased twofold. Similar results were obtained with glutathione S-transferase (EC 2.5.1.18) activity which increased by 60% with diet S600. After AFB1 treatment, a general increase in the activities of the above enzymes was found, except for UDPGT in the group fed on diet S600. When rats were fed on the diet without S. nigrum, AFB1 induced an increase in alkaline phosphatase (ALP) (EC 3.1.3.1), aspartate aminotransferase (AST) (EC 2.6.1.1) and gamma-glutamyltransferase (gamma-GT) (EC 2.3.2.2) levels in the serum. AFB1 also induced increases in serum ALP and gamma-GT levels when rats were fed on diet S600.