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Anopheles (Cellia) carnevalei is described in the mainland region (Río Muni) of Equatorial Guinea. Anophelines collected were identical to An. nili with exception of some morphological characters found in wings, head, and legs.
Nine Y-STR loci from the "minimal haplotype" included in Y-STR Haplotype Reference Databases (YHRD) together with eight additional Y-STRs (DYS437, DYS438, DYS439, DYS460, DYS461, GATA C4, GATA H4 and GATA A10) were analyzed in a sample of 101 males from Equatorial Guinea living in Madrid. Haplotype and allelic frequencies were calculated and genetic diversities were estimated for each genetic system as well as for the whole haplotype. An unexpected high frequency (6%) of intermediate alleles (13.2 and 14.2) was found in DYS385. For DYS19, two alleles were found in one sample. Another sample failed to amplify with DYS393 primers using either PowerPlex Y System (Promega Corporation) or the Y-PLEXtrade mark 12 (Reliagene, New Orleans, LA) commercial kits. Comparison between Equatorial Guinea and another African population (Mozambique; South East Coast) revealed a significant pairwise Phi(st) value between them (Phi(st)=0.03309; P=0.00000).
A seroparasitological study of malaria was carried out in two of the more important islands of Equatorial Guinea, Bioko (ex Fernando Poo) and Annobón. The study involved a randomly-chosen population of children aged from two to nine years. In Bioko 1130 children were chosen from 29 of the 51 villages on the island; in Annobón 185 children were chosen from the capital town, where all the population lived. Indirect immunofluorescence tests (IFAT) showed a prevalence of malaria infection of 29.8% in Bioko and 55.7% in Annobón. The parasitic prevalence (malaria index) was 26.6% and 55.1% respectively, and the splenic index was 57.0% and 54.6% respectively. The results indicate that this is an area of stable hyperendemic malaria, which may benefit from an antimalarial programme.
The current study was performed on the Bioko Island (Equatorial Guinea) with the aim of establishing a rapid assessment technique for mapping malaria risk and measuring vector densities. Human bait collection, tent traps, light traps, indoor resting collection, and window exit traps were used to collect Anopheles gambiae s.s. and Anopheles funestus, the two anopheline species involved in malaria transmission in this island. Capture data were used to compare differences in the behavior and vectorial capacity of An. gambiae s.s. and An. funestus. Differences in the two species of mosquitoes were found in relation to the season and trapping methods used. Entomological inoculation rates (EIR) for Plasmodium falciparum were calculated using a polymerase chain reaction (PCR) test with individual anopheline mosquitoes from human bait collections in two villages during the dry and rainy seasons. P. falciparum sporozoites were detected from both dissected heads/thorax and abdomens of both species.
Onchocerciasis is endemic on the island of Bioko, Equatorial Guinea, where it is transmitted by the 'Bioko form' of the Simulium damnosum complex, a cytospecies unique to the island. To determine the distribution of vector breeding, three dry season and two wet season expeditions were made in 1989, 1996 and 1997, and 226 of the island's 247 rivers (91.5%) were visited. Of these 226 rivers, 130 (58%) were flowing during the dry season, forty-five (20%) supported aquatic stages of Simuliidae of any species and twenty-five (11%) contained larvae or pupae of the S. damnosum complex. The twenty-one rivers not prospected were in the mountainous south of the island, where an additional seventeen rivers were reached but not satisfactorily prospected. Of these thirty-eight rivers, twenty-nine were considered highly likely to support vector breeding, bringing the total number of rivers which could harbour the vector during the dry season to fifty-four (21.9% of the island's total). Breeding was believed to be limited to river stretches below 1000 m altitude, and during the dry season the total length of those stretches which could support breeding on Bioko was estimated to be 1020 km. A combination of factors, including low river discharges during the dry season, the relatively low water temperature on Bioko, the suitability of limited stretches of most rivers as vector breeding sites and the close proximity of many rivers within a small geographical area, render the vector vulnerable to eradication by aerial treatment of rivers with insecticide. The isolation of the Bioko form of the S. damnosum complex suggests that reinvasion following treatment would be unlikely, and eradication of the vector might be achieved by a dry season larviciding programme in one or two years.
The integration of schistosomiasis control with the activities of different endemic disease control or health programmes has been endorsed by a WHO Expert Committee on the Control of Schistosomiasis (WHO 1985). Endemic countries face increasing economic and manpower constraints which limit the coverage and effectiveness of control activities. Integration would be expected to optimize available resources for control. The feasibility of integration can be assessed by a comparative evaluation of: the epidemiology and distribution of the health problems; the techniques and methodology of control; and the requirements for maintenance and their relative health importance. This report presents a preliminary assessment of trypanosomiasis and schistosomiasis in Equatorial Guinea. The background and implementation of the operational national trypanosomiasis control programme are summarized. Population-based epidemiological investigations undertaken by the staff of the trypanosomiasis control programme are reported from a rural village and an urban suburb of Bata, Equatorial Guinea. The distribution and morbidity of S. intercalatum are compared, the public health importance of S. intercalatum is reviewed and the feasibility of integration of control of trypanosomiasis and schistosomiasis are assessed.
We determined the HLA frequency distribution in a sample of 100 Bubi individuals born on the island of Bioko (Equatorial Guinea). HLA-A, -B and -C typing was performed by serology and PCR-SSP. DRB1/3/4/5, DQB1 and DQA1 alleles were determined by PCR-SSOP. The HLA allele distribution of this population group resembles those found in other Bantu-speaking groups; however, the higher frequency of A30, A32, B44, DRB1*1301 in the Bubi with respect to other Bantu groups and the absence of DR4 deserve special mention. The cloning and sequencing of class I and II genes in this population allowed the description of five new allelic variants: B*4407, Cw*0706, Cw*1801, Cw*1802 and DQB1*0612 and five confirmatory sequences: B*3910, B*5703, B*8101, Cw*1203 and Cw*1701. The following new HLA-C,B haplotypes have been found in Bubi: Cw*08-B*57, Cw*18-B*57, Cw*0302-B*53, Cw*07-B*53 and Cw*1601-B*63. The most frequent seven-locus haplotype is: A*30-Cw*17-B*42-DRB1*1102-DRB3*0202-DQA1*05-DQB1 *0301. In terms of genetic distance, the Bubi are closer to other Bantu groups than to West African populations.
The Bioko Island Malaria Control Project was initiated in 2003 to substantially reduce malaria on the island of Bioko in Equatorial Guinea. The intervention consisted of generalized indoor residual spraying during the first year of the project. Case management and related measures were introduced during the second year. Two large household and parasitemia surveys of children 2 to < 15 years of age were carried out in 2004 and 2005, respectively, to assess the effect of the intervention after the first year. Patient records were collected retrospectively from one district hospital and analyzed for a comparison of pre-intervention and post-intervention periods. Overall mean prevalence of P. falciparum infection reduced from 46% (95% confidence interval [CI] = 40-51%) at baseline in 2004 to 31% (95% CI = 24-40%) in 2005 (P < 0.001). When the 12-month pre-intervention period was compared with the 12-month post-intervention period, there was a modest but statistically significant reduction in the number of malaria cases among hospital patients.
A survey for the prevalence, geographical distribution and clinical manifestations of onchocerciasis was conducted on the Island of Bioko (formerly Fernando Póo), Equatorial Guinea, between 1987-89. The whole population (1799 inhabitants) of thirteen villages distributed around the island was surveyed. Identification data, physical examination and Snellen "E" test for visual acuity were performed. Skin snips were taken from both iliac crests and right scapula and calf. Differential diagnosis between Onchocerca volvulus and Mansonella streptocerca was carried out in both fresh and Giemsa stained preparations. The overall prevalence (+ skin snips) and mean microfilarial density were 75.2% (range 51.9% to 87.1%) and 32.2 mf/snip respectively. Skin snips showed a higher microfilarial density from iliac crests. The following clinical manifestations were found: 560 (31.2%) with nodules; 518 (28.8%) with dermatitis, pigmentation changes and cutaneous atrophy; 753 (41.9%) with lymphoadenopathy and lymphoedema. Blindness due to different causes was registered in 13 cases (0.8%). The results showed that onchocerciasis is hyperendemic and widespread over the island. It is estimated that almost the whole population (62,000) is at risk of infection.
AIMS: This study was designed to estimate the prevalence of blindness and its main aetiologies in Bioko, an onchocerciasis endemic zone of Equatorial Guinea. METHODS: Random sampling was applied, proportionally to population distribution into urban or rural areas. All the subjects underwent a basic eye examination by trained nurses. In the presence of any ocular affection or a visual acuity of less than 0.3, the subject was visited by the ophthalmologist. This visit included direct and indirect ophthalmoscopy, anterior segment examination with a slit lamp, and intraocular pressure recording. Blindness and visual impairment were defined by using the WHO criteria. RESULTS: 3218 subjects were screened, with a mean age of 34.1 (SD 21.6) years, ranging from 1 month to 102 years (median 34 years). The overall prevalence of blindness was 3.2% (95% CI: 2.6% to 3.9%). Unilateral blindness was present in 4.2%. Visual impairment was diagnosed in 200 patients (6.8%). More than 20% of the acuities inferior to 0.7 improved when explored with a pinhole. The main causes of blindness were cataracts (61.3%); macular affection (25.3%), optic atrophy (16%), and glaucoma (13.3%). Ocular onchocerciasis was detected in 12 cases (0.4%). CONCLUSION: Ocular onchocerciasis was very uncommon in an area of high endemicity. Results also pointed at the lack of basic ophthalmologist eye care and optician resources in the island.
This is the first description of 3rd and 4th instars of Anopheles (Cellia) carnevalei. Adults were caught in the mainland region (Rio Muni) of Equatorial Guinea. Larvae present characteristic palmate setae different from Anopheles nili.
Eighteen cases of confirmed AIDS with cryptococcal meningitis in Bata Regional Hospital, Equatorial Guinea from January 1997 to November 1999 were analysed. The associated morbidity and mortality rates were very high. Contributory factors were the failure to note the occurrence of AIDS with cryptococcal meningitis, late presentation, serious illness and severe complications, and delayed and inadequate therapy.
We illustrate the use of Faith's 'Phylogenetic Diversity' measure to compare the phylogeographic structure of two bird species with patterns of avian endemism across six mountains in Cameroon and Equatorial Guinea. The Mountain Greenbul and Cameroon Blue-headed Sunbird showed phylogeographic patterns that together defined three biogeographic regions: Bioko, Mt. Cameroon, and the northern mountains of Cameroon. In contrast, the distributions of endemic species were largely a function of geographical distance, with close mountains sharing more endemic species than distant mountains. Moreover, for both species, populations on Mt. Cameroon were distinctive with respect to the ecologically relevant character bill size. Our results, while preliminary, illustrate the utility of a comparative approach for identifying geographical regions that harbour evolutionarily distinct populations and caution against using only the distributional patterns of endemics to prioritize regions for conservation. Results show that patterns of endemism may not be concordant with patterns of phylogenetic diversity nor morphological variation in a character important in fitness. While incorporation of additional species from unrelated taxa will be necessary to draw definitive conclusions about evolutionarily distinct regions, our preliminary results suggest a conservation approach for the Afromontane region of the Gulf of Guinea that would: (i) emphasize protection of both Bioko and Mt. Cameroon, thereby maximizing preservation of within-species phylogenetic and morphologic diversity; (ii) emphasize protection within the northern mountains to further conserve intraspecific phylogenetic diversity and maximize protection of endemic species.
SETTING: Five districts in Equatorial Guinea, March 1999 to February 2001. OBJECTIVES: To determine tuberculosis drug resistance among new and previously treated cases, the risk factors associated with resistance, and the mutations associated with isoniazid and rifampicin (katG, inhA and rpoB genes) resistance, and to genotype resistant strains. RESULTS: A positive culture identified as Mycobacterium tuberculosis complex was obtained in 240/499 patients. Susceptibility testing was performed in 236 strains. The overall resistance rate in new cases was 16.9% compared to 41.6% in previously treated cases. Isoniazid resistance was the most frequent (respectively 12.5% and 16.6%) in the two groups, while multidrug resistance was observed in 1.7% and 25% of new and previously treated cases, respectively. Female sex was statistically associated with resistance in new cases. Of 41 isoniazid-resistant strains, 33 (80.5%) had mutations in the inhA gene; none had mutations in the katG gene and eight had no mutations in either gene. All strains had low-level isoniazid resistance. Of eight strains resistant to rifampicin, six had mutations in the rpoB gene. Genotyping defined seven clusters. CONCLUSIONS: Moderate resistance was found in new cases. Low-level isoniazid resistance predominated among mutations in the inhA gene, with a high percentage of clustering in resistant strains.
Allele frequencies for eight STR loci (HUMTH01, HUMVWA31A, HUMCSF1PO, HUMTPOX, D3S1358, D8S1179, D18S51, D19S253) have been analysed in the Bubi population of Bioko Island, Equatorial Guinea. For all loci, no deviation from Hardy-Weinberg equilibrium was found. Data obtained were compared with that of Caucasian and African populations. Significant differences were found for all systems between all the black populations compared and the Caucasoid population. Similarities were observed between the Bubi and Zimbabweans, and also with African American populations. Also, more affinities were observed between Zimbabweans and Ugandans and Ovambos than between these groups and the Bubi population. From these comparisons it is suggested that in Africa, as in other continents, there is a certain genetic heterogeneity.
The invasive oriental mosquito Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) was detected on Bioko Island for the first time in November 2001. It was found to be well established breeding in artificial containers at Planta, near Malabo, the capital of Equatorial Guinea. Associated species of mosquito larvae were Aedes aegypti (L.), Ae. africanus (Theobald), Culex near decens Theobald, Cx. duttoni Theobald, Cx. quinquefasciatus Say, Cx. tigripes De Grandpré & De Charmoy, Eretmapodites quinquevittatus Theobald and Mansonia africana (Theobald). This is the third tropical African country to be invaded by Ae. albopictus, which has recently spread to many parts of the Americas and Europe--with vector competence for dengue, yellow fever and other arboviruses. In the Afrotropical environment, it will be interesting to monitor the ecological balance and/or displacement between introduced Ae. albopictus and indigenous Ae. aegpyti (domestic, peri-domestic and sylvatic populations).
In West Africa, Anopheles gambiae exists in discrete subpopulations known as the M and S molecular forms. Although these forms occur in sympatry, pyrethroid knock-down resistance (kdr) is strongly associated with the S molecular form. On the island of Bioko, Equatorial Guinea we found high frequencies of the kdr mutation in M form individuals (55.8%) and a complete absence of kdr in the S form. We also report the absence of the kdr allele in M and S specimens from the harbour town of Tiko in Cameroon, representing the nearest continental population to Bioko. The kdr allele had previously been reported as absent in populations of An. gambiae on Bioko. Contrary to earlier reports, sequencing of intron-1 of this sodium channel gene revealed no fixed differences between M form resistant and susceptible individuals. The mutation may have recently arisen independently in the M form on Bioko due to recent and intensive pyrethroid application.
The HLA-Cw*1801 specificity, a Cw7/Cw4 hybrid allele, has recently been described in association with B*8101 (formerly B"DT"). In this study, the new Cw*1802 variant, differing from Cw*1801 at exon 5, is found associated with B*5703 in Bubi individuals from Equatorial Guinea. Confirmatory complete coding regions of B*5703 and B*3910 are also reported.