Neutralisation of Local Haemorrhage Induced by the Saw-Scaled Viper Echis carinatus sochureki Venom Using Ethanolic Extract of Hibiscus aethiopicus L.

The objective of the study is to investigate the anti-snake venom activities of a local plant, Hibiscus aethiopicus L. The H. aethiopicus was dried and extracted with ethanol. Different assays were performed according to standard techniques, to evaluate the plant's acute toxicity and its antivenom activities. The results of evaluating the systemic acute toxicity of the H. aethiopicus extract using "oral and intra-peritoneal" route were normal even at the highest dose (24 g/kg) tested. All guinea pigs (n = 3) when treated with venoms E. c. sochureki (75 µg) alone induced acute skin haemorrhage. In contrast, all guinea pigs (n = 18) treated with both venom and the plant extract at a concentration between 500 and 1000 mg/kg showed no signs of haemorrhage. Moreover, all guinea pigs (n = 18) treated with venom and the plant extract below 400 mg/kg showed acute skin haemorrhage. All guinea pigs treated with venom E. c. sochureki (75 µg) alone induced acute skin haemorrhage after both 24 and 32 hours. In contrast, all guinea pigs treated with both venom and the plant extract (administered independently) at concentrations between 500 and 1000 mg/kg showed no signs of haemorrhage after 32 hours. However, after 24 hours all tested guinea pigs showed less inhibition (<60%) compared to that obtained after 32 hours. The outcome of this study reflects that the extract of H. aethiopicus plant may contain an endogenous inhibitor of venom induced local haemorrhage.

Hepatitis B virus carrier rate, prevalence and susceptibility and impact of immunization program among households in the city of Taiz, Yemen.

OBJECTIVE: To examine the carrier rate, prevalence and susceptibility to hepatitis B virus infection in the city of Taiz, Yemen. METHODS: In a community-based household survey 521 subjects from 98 randomly selected households were enrolled. Carrier rate, prevalence and susceptibility of hepatitis B virus infection in the city of Taiz, Yemen were examined. RESULTS: The median age of the subjects was 19 years (range <1-85 years), 219 (42.0%) of whom were males and 305 (58.0%) were females. The HBsAg carrier rate was 4.2% (22/521), the prevalence was 16.9% (88/521) and the susceptibility rate was 57.5% (287/499). Male vs female carrier rate, prevalence and susceptibility rate were comparable. Children (age ≤ 18 years) vs adults had carrier rates of 2.7% vs 5.7% (odds ratio=2.2) and a prevalence of 5.1% vs 28.4% (OR: 5.6). The carrier rate, prevalence and immunity to HBV among subjects who reported vaccination vs those unvaccinated was; 2.1% vs 5.5%, 11.3 vs 20.8% and 53.1% vs 18.8%. A proportion of 47.2% of subjects who aged ≤ 10 years had isolated anti-HBs. Of 142 of the cohort born after full implementation of vaccination program (age:≤ 9 years) 72 (50.7%) were immune and 70 (49.3%) were susceptible whereas of 357 subjects borne before program implementation (Age:≥ 10 years) 140 (39.2%) were immune and 217 (60.8%) were susceptible (p<0.02 (Pearson) OR: 1.6 CI=0.42-0.93). CONCLUSIONS: An intermediate endimicity was identified in Taiz city. Vaccination reduced carrier rate prevalence and susceptibility among vaccinated subjects. The high rate of subjects with isolated anti- HBs together with the reduced susceptibility rate among the cohort born after inclusion of HBV vaccine to EPI reflects impact of the program. Improving vaccination coverage will further reduce susceptibility rate.

Serine protease variants encoded by Echis ocellatus venom gland cDNA: cloning and sequencing analysis.

Envenoming by Echis saw-scaled viper is the leading cause of death and morbidity in Africa due to snake bite. Despite its medical importance, there have been few investigations into the toxin composition of the venom of this viper. Here, we report the cloning of cDNA sequences encoding four groups or isoforms of the haemostasis-disruptive Serine protease proteins (SPs) from the venom glands of Echis ocellatus. All these SP sequences encoded the cysteine residues scaffold that form the 6-disulphide bonds responsible for the characteristic tertiary structure of venom serine proteases. All the Echis ocellatus EoSP groups showed varying degrees of sequence similarity to published viper venom SPs. However, these groups also showed marked intercluster sequence conservation across them which were significantly different from that of previously published viper SPs. Because viper venom SPs exhibit a high degree of sequence similarity and yet exert profoundly different effects on the mammalian haemostatic system, no attempt was made to assign functionality to the new Echis ocellatus EoSPs on the basis of sequence alone. The extraordinary level of interspecific and intergeneric sequence conservation exhibited by the Echis ocellatus EoSPs and analogous serine proteases from other viper species leads us to speculate that antibodies to representative molecules should neutralise (that we will exploit, by epidermal DNA immunization) the biological function of this important group of venom toxins in vipers that are distributed throughout Africa, the Middle East, and the Indian subcontinent.

Antisnake Venom Activity of Hibiscus aethiopicus L. against Echis ocellatus and Naja n. nigricollis.

The objective of the study is to investigate whether the Hibiscus aethiopicus L. plant has neutralization activity against venoms of two clinically important snakes. The H. aethiopicus was dried and extracted with water. Different assays were performed to evaluate the plant's acute toxicity and its anti-snake venom activities. The results showed that H. aethiopicus extract alone had no effect on the viability of C(2)C(12) muscle cells, but significantly (P < .05) protected muscle cells against the toxic effects of E. ocellatus venom at 55, 150, and 300 mug/mL. The maximum protective effect of the extract was exhibited at 75 mug/mL. The extract significantly (P < .001) inhibited the cytotoxic effects of E. ocellatus venom at 300 mug/mL. All rabbits (n = 10) and guinea pigs (n = 10) were alive after the two weeks of given the lethal dosage 16 g/Kg of the H. aethiopicus extract herbal solution. No abnormal behaviour was observed of both groups of animals. All guinea pigs (n = 3) treated with venoms alone (5 mg/kg) died. However, all guinea pigs (n = 21) treated with venom (5 mg/kg) and the extract (400 to 1000 mg/kg) survived. Guinea pigs (n = 3) treated with Naja n. nigricollis venom alone (2.5 mg/kg) and guinea pigs (n = 21) venom with the extract (400 to 1000 mg/kg) died. The H. aethiopicus completely (100%) blocked the haemorrhagic activity of E. ocellatus in the egg embryo at 3.3 mg/mL of extract. These findings suggest that H. aethiopicus may contain an endogenous inhibitor of venom-induced haemorrhage.

Prevalence of antibodies to measles and rubella in Sana'a, Yemen.

Prevalence of antibodies to measles and rubella was tested in sera collected from 1368 subjects in urban and rural Sana'a. Overall, 11.7% had no antibodies to measles and 14.6% had no antibodies to rubella, despite the fact that measles but not rubella vaccine is included in the vaccination program in Yemen. Of 89 children <5 years of age 49 (55.1%) had no detectable antibodies to measles, demonstrating that supplementary measles immunization campaigns are required to prevent virus circulation. Assessment of measles immune status among infants in the first year of life is required to determine the optimum age for measles vaccination. Rubella vaccination should be considered with care in Yemen.

Prevalence of blood-borne viral hepatitis in different communities in Yemen.

It is generally believed that hepatitis B (HBV) and C (HCV) viruses are highly prevalent in the Republic of Yemen. This study investigated the prevalence of HBV and HCV markers in 494 blood donors from Aden, 493 blood donors from Sana'a, 97 residents from an African ethnic minority in Sana'a and 99 residents of Soqotra Island. There were significant differences in the prevalence of HBV carriage (HBsAg: 6.7, 15, 19.6 and 26.3% respectively; P < 0.001); past HBV infection (anti-HBc: 17.4, 18.5, 30.9 and 59.6% respectively; P < 0.001); susceptibility to HBV (absence of HBV markers: 73.3, 61.9, 38.1 and 9.1% respectively; P < 0.001), infectivity of HBV carriers (HBV DNA: 51.5, 33.8, 52.6 and 65.4% respectively; P = 0.028) and HCV antibodies (RIBA confirmed or indeterminate: 0.6, 0.2, 5.2 and 5.1% respectively; P < 0.001). A significant difference in HBV carrier rate and a borderline significant difference in the prevalence of natural infection was observed between males and females in the African community (P = 0.02 and 0.06 respectively). In contrast, in Soqotra Island, there was no significant sex difference in HBV carrier rate but susceptibility was significantly more prevalent in males (P = 0.03). This study illustrates that significant difference in prevalence and epidemiology exists among different communities within the same country, reflecting political, geographical and social differences. Control strategies should take these differences into account.

Prevalence of rubella antibodies among schoolgirls in Sana'a, Republic of Yemen.

To determine the prevalence of rubella antibodies and age of exposure to rubella among Yemeni schoolgirls, we studied the sera samples of 323 female students (age range 11-21 years; mean age 16.26 +/- 1.89 years) drawn from three schools in Sana'a. All samples were screened for rubella IgG antibodies using enzyme linked immunosorbent assay and, if negative, for IgM in order to exclude the possibility of recent exposure. Of 323 sera, 296 (91.64%) were positive for rubella IgG. All IgG negative sera were also IgM negative. Comparable antibody prevalence was observed in all age groups. The prevalence of rubella IgG among Yemeni schoolgirls is high, with most becoming immune between the ages of 11 and 21 years. Although the age of exposure seems to be < or = 13 years, further investigation is needed to confirm this.

Prevalence of rubella antibodies among schoolgirls in Sana'a, Republic of Yemen

To determine the prevalence of rubella antibodies and age of exposure to rubella among Yemeni schoolgirls, we studied the sera samples of 323 female students [age range 11-21 years; mean age 16.26 +/- 1.89 years] drawn from three schools in Sana'a. All samples were screened for rubella IgG antibodies using enzyme linked immunosorbent assay and, if negative, for IgM in order to exclude the possibility of recent exposure. Of 323 sera, 296 [91.64%] were positive for rubella IgG. All IgG negative sera were also IgM negative. Comparable antibody prevalence was observed in all age groups. The prevalence of rubella IgG among Yemeni schoolgirls is high, with most becoming immune between the ages of 11 and 21 years. Although the age of exposure seems to be </= 13 years, further investigation is needed to confirm this

Hepatitis G virus RNA and its relation to hepatitis C infection in adult haemophilic patients.

The prevalence of hepatitis C virus (HCV) infection and hepatitis G virus (HGV) RNA were studied in 50 adult haemophilic patients who had received commercial clotting factors prior to 1980. HGV RNA was detectable in 6/ 50 patients (12%); 49/50 (98%) had antibody to HCV and 40/49 (82%) of these were viraemic with detectable HCV RNA; 5/6 patients with detectable HGV RNA had co-existing HCV infection and viraemia. The HGV PCR products from all six patients were directly sequenced and all were shown to be similar to that of HGV but more diverse from that of GB virus C. One patient who had persistent abnormal liver function tests had detectable HGV RNA but no evidence of hepatitis B or C. The presence of HGV RNA in the absence of hepatitis B and C infection indicates that this virus is capable of independent transmission. Independent response to interferon was demonstrated in one patient with co-infection who lost HGV but not HCV after interferon therapy.