Entomological risk assessment for transmission of arboviral diseases by Aedes mosquitoes in a domestic and forest site in Accra, Ghana.

Dengue, Zika and chikungunya are Aedes-borne viral diseases that have become great global health concerns in the past years. Several countries in Africa have reported outbreaks of these diseases and despite Ghana sharing borders with some of these countries, such outbreaks are yet to be detected. Viral RNA and antibodies against dengue serotype-2 have recently been reported among individuals in some localities in the regional capital of Ghana. This is an indication of a possible silent transmission ongoing in the population. This study, therefore, investigated the entomological transmission risk of dengue, Zika and chikungunya viruses in a forest and domestic population in the Greater Accra Region, Ghana. All stages of the Aedes mosquito (egg, larvae, pupae and adults) were collected around homes and in the forest area for estimation of risk indices. All eggs were hatched and reared to larvae or adults for morphological identification together with larvae and adults collected from the field. The forest population had higher species richness with 7 Aedes species. The predominant species of Aedes mosquitoes identified from both sites was Aedes aegypti (98%). Aedes albopictus, an important arbovirus vector, was identified only in the peri-domestic population at a prevalence of 1.5%, significantly higher than previously reported. All risk indices were above the WHO threshold except the House Index for the domestic site which was moderate (19.8). The forest population recorded higher Positive Ovitrap (34.2% vs 26.6%) and Container (67.9% vs 36.8%) Indices than the peri-domestic population. Although none of the mosquito pools showed the presence of dengue, chikungunya or Zika viruses, all entomological risk indicators showed that both sites had a high potential arboviral disease transmission risk should any of these viruses be introduced. Continuous surveillance is recommended in these and other sites in the Metropolis to properly map transmission risk areas to inform outbreak preparedness strategies.

Indication of Risk of Mother-to-Child Toxoplasma gondii Transmission in the Greater Accra Region of Ghana.

Objectives Congenital infection with Toxoplasma gondii is known to result in neurological and brain disorders including ophthalmic disorders later in life. Research in Ghana revealed high sero-prevalence among pregnant women and eye patients. This study determines the risk of congenital transmission of T. gondii infection in Accra, Ghana. Methods One hundred consented pregnant women aged 18-45 years (mean 29.85 ± 5.76) participated. Venous blood and tissue samples were taken from the maternal side of each placenta after delivery. Cord blood samples were also taken after they were separated from the infants. Finger-prick blood was taken from infants of participating women at 2 or 6 weeks post-natal. ELISA was used to detect T. gondii antibodies in all blood samples while Nested-PCR was used to detect T. gondii DNA from placental tissues. Data was analysed using SPSS v. 16. Results Overall, 37.6 % of maternal blood, 39.5 % of umbilical cord blood, and 57.5 % of post-natal infant blood were positive for anti-T. gondii IgG. No anti-T. gondii IgM was detected in any of those samples. Toxoplasma gondii DNA was detected in 39.8 % of placental tissue samples. Strong association was observed in the occurrence of placental T. gondii DNA and anti-T. gondii IgG positive women (ø = 0.810, p < 0.00001) as well as high Relative risk shown in the likelihood of foetal exposure to infection in latently-infected women (RR 10.39; CI 4.47-24.17; p < 0.00001). Conclusions for Practice The presence of anti-T. gondii IgG antibodies only, and T. gondii DNA in placental tissues indicate the women might have been infected early during the pregnancy, placing about 39.8 % of the babies at risk. These results can strongly influence policy to screen and treat pregnant women for T. gondii infection.

New anti-trypanosomal active tetracyclic iridoid isolated from Morinda lucida Benth.

Human African trypanosomiasis (HAT), commonly known as sleeping sickness has remained a serious health problem in many African countries with thousands of new infected cases annually. Chemotherapy, which is the main form of control against HAT has been characterized lately by the viewpoints of toxicity and drug resistance issues. Recently, there have been a lot of emphases on the use of medicinal plants world-wide. Morinda lucida Benth. is one of the most popular medicinal plants widely distributed in Africa and several groups have reported on its anti-protozoa activities. In this study, we have isolated one novel tetracyclic iridoid, named as molucidin, from the CHCl3 fraction of the M. lucida leaves by bioassay-guided fractionation and purification. Molucidin was structurally elucidated by (1)H and (13)C NMR including HMQC, HMBC, H-H COSY and NOESY resulting in tetracyclic iridoid skeleton, and its absolute configuration was determined. We have further demonstrated that molucidin presented a strong anti-trypanosomal activity, indicating an IC50 value of 1.27 µM. The cytotoxicity study using human normal and cancer cell lines indicated that molucidin exhibited selectivity index (SI) against two normal fibroblasts greater than 4.73. Furthermore, structure-activity relationship (SAR) study was undertaken with molucidin and oregonin, which is identical to anti-trypanosomal active components of Alnus japonica. Overlapping analysis of the lowest energy conformation of molucidin with oregonin suggested a certain similarities of aromatic rings of both oregonin and molucidin. These results contribute to the future drug design studies for HAT.