Absence of putative artemisinin resistance mutations among Plasmodium falciparum in Sub-Saharan Africa: a molecular epidemiologic study

Plasmodium falciparum parasites that are resistant to artemisinins have been detected in Southeast Asia. Resistance is associated with several polymorphisms in the parasite's K13-propeller gene. The molecular epidemiology of these artemisinin resistance genotypes in African parasite populations is unknown. We developed an assay to quantify rare polymorphisms in parasite populations that uses a pooled deep-sequencing approach to score allele frequencies, validated it by evaluating mixtures of laboratory parasite strains, and then used it to screen P. falciparum parasites from >1100 African infections collected since 2002 from 14 sites across sub-Saharan Africa. We found no mutations in African parasite populations that are associated with artemisinin resistance in Southeast Asian parasites. However, we observed 15 coding mutations, including 12 novel mutations, and limited allele sharing between parasite populations, consistent with a large reservoir of naturally occurring K13-propeller variation. Although polymorphisms associated with artemisinin resistance in P. falciparum in Southeast Asia are not prevalent in sub-Saharan Africa, numerous K13-propeller coding polymorphisms circulate in Africa. Although their distributions do not support a widespread selective sweep for an artemisinin-resistant phenotype, the impact of these mutations on artemisinin susceptibility is unknown and will require further characterization. Rapid, scalable molecular surveillance offers a useful adjunct in tracking and containing artemisinin resistance.

Risk factors for trachoma in Mali

OBJECTIVES

Prior to commencing a campaign to eliminate blinding trachoma in Mali, a national disease prevalence survey was conducted from March 1996 to June 1997. The prevalence of trachoma was estimated and potential risk factors were studied.

METHODS

In each of Mali's seven regions (excluding the capital Bamako), a sample of 30 clusters was taken from the general population, in accordance with the principle of probability proportional to the size of the community. All children under 10 years of age were examined. The simplified clinical coding system proposed by the World Health Organization was used. The position of each village was established and subsequently related to the nearest meteorological station. Socioeconomic and environmental information was collected at both village and household level. The mother or caretaker of each child was questioned about availability and use of water for washing the child. At the time of examination, facial cleanliness and the presence of flies on the face were noted.

RESULTS

A total of 15,187 children under 10 years of age were examined. The prevalence of active trachoma (follicular [TF] or intense trachoma [TI]) was 34.9% (95% CI : 32.3-37.6) and the prevalence of TI was 4.2% (95% CI : 3.5-5.0). Aridity/environmental dryness appears to be a risk factor influencing the current geographical distribution of trachoma. Small villages had considerably higher trachoma prevalence than their larger neighbours. The proximity of a medical centre and the existence of social organizations such as a women's association were associated with lower levels of trachoma. Crowded living conditions increased the risk. Using a monetary marker of wealth, we observed a linear inverse relation between wealth and trachoma prevalence. The presence of a dirty face was strongly associated with trachoma (odds ratio [OR] = 3.67) as was the presence of flies on the child's face (OR = 3.62). Trachoma prevalence increased with distance to a water source. Disease prevalence decreased with a higher frequency of both face washing and bathing.

CONCLUSIONS

Of all the risk factors examined, facial cleanliness had the strongest association with the prevalence of trachoma. This was followed by the presence of flies on the child's face. Both face washing and bathing showed beneficial effects. Socioeconomic factors such as wealth were significantly explanatory. It is likely that hygiene education and fly control by environmental improvement could have a very significant impact on the prevalence of trachoma in Mali.

Modulation of invasive properties of murine squamous carcinoma cells by heterologous expression of cathepsin B and cystatin C

Murine SCC-VII squamous carcinoma cells have the capacity to penetrate reconstituted basement membranes (Matrigel) in vitro. The invasion of Matrigel layers by SCC-VII cells was significantly reduced by E-64, a specific inhibitor of lysosomal cysteine proteinases. The cathepsin-B-selective E-64 derivative, CA-074, inhibited penetration of Matrigel by SCC-VII cells to the same extent, indicating a major role for this particular lysosomal enzyme in extracellular-matrix degradation during squamous-carcinoma-cell invasion. SCC-VII cells were stably transfected with a cDNA encoding human procathepsin B, in an attempt to modulate the invasive properties of the cell line. The transfected cells expressed the heterologous gene, secreted increased amounts of procathepsin B and displayed enhanced invasive potential. In vivo, the activity of cathepsin B is strictly regulated by endogenous inhibitors. SCC-VII cells were therefore also stably transfected with a cDNA encoding human cystatin C, the most potent cysteine-proteinase inhibitor in mammalian tissues. The expression of this transgene resulted in the production of active recombinant cystatin C and a pronounced reduction in Matrigel invasion. These studies demonstrate that the invasive properties of squamous-cell carcinomas can be changed by modulation of the balance between cathepsin B and its endogenous inhibitors, and provide further evidence for the involvement of this lysosomal cysteine proteinase in tumour invasion and metastasis.

The nonreplicating smallpox candidate vaccines defective vaccinia Lister (dVV-L) and modified vaccinia Ankara (MVA) elicit robust long-term protection

Current smallpox vaccines are live vaccinia viruses that replicate in the vaccinee inducing immunity against the deadly disease smallpox. Replication resulting in virus spread within the host, however, is the major cause of severe postvaccinal adverse events. Therefore, attenuated strains such as modified vaccinia Ankara (MVA) or LC16m8 are candidates as next generation vaccines. These strains are usually grown in primary cells in which mass production is difficult and have an unknown protective potential in humans. Proven vaccine strains of defined origin and modern production techniques are therefore desirable. In this study, defective vaccinia virus (dVV) lacking a gene essential for replication (derived from the Lister vaccine in a complementing cell line) was compared with the Wyeth smallpox vaccine strain and with MVA in mouse animal models using cowpox and ectromelia virus challenge. Similar to MVA, prime-boost immunizations with defective vaccinia induced robust long-term immunity, suggesting it as a promising next generation smallpox vaccine.

Immunogenicity and safety of defective vaccinia virus lister: comparison with modified vaccinia virus Ankara

Potent and safe vaccinia virus vectors inducing cell-mediated immunity are needed for clinical use. Replicating vaccinia viruses generally induce strong cell-mediated immunity; however, they may have severe adverse effects. As a vector for clinical use, we assessed the defective vaccinia virus system, in which deletion of an essential gene blocks viral replication, resulting in an infectious virus that does not multiply in the host. The vaccinia virus Lister/Elstree strain, used during worldwide smallpox eradication, was chosen as the parental virus. The immunogenicity and safety of the defective vaccinia virus Lister were evaluated without and with the inserted human p53 gene as a model and compared to parallel constructs based on modified vaccinia virus Ankara (MVA), the present "gold standard" of recombinant vaccinia viruses in clinical development. The defective viruses induced an efficient Th1-type immune response. Antibody and cytotoxic-T-cell responses were comparable to those induced by MVA. Safety of the defective Lister constructs could be demonstrated in vitro in cell culture as well as in vivo in immunodeficient SCID mice. Similar to MVA, the defective viruses were tolerated at doses four orders of magnitude higher than those of the wild-type Lister strain. While current nonreplicating vectors are produced mainly in primary chicken cells, defective vaccinia virus is produced in a permanent safety-tested cell line. Vaccines based on this system have the additional advantage of enhanced product safety. Therefore, a vector system was made which promises to be a valuable tool not only for immunotherapy for diseases such as cancer, human immunodeficiency virus infection, or malaria but also as a basis for a safer smallpox vaccine.

A Non-Inferiority, Individually Randomized Trial of Intermittent Screening and Treatment versus Intermittent Preventive Treatment in the Control of Malaria in Pregnancy

BACKGROUND

The efficacy of intermittent preventive treatment for malaria with sulfadoxine-pyrimethamine (IPTp-SP) in pregnancy is threatened in parts of Africa by the emergence and spread of resistance to SP. Intermittent screening with a rapid diagnostic test (RDT) and treatment of positive women (ISTp) is an alternative approach.

METHODS AND FINDINGS

An open, individually randomized, non-inferiority trial of IPTp-SP versus ISTp was conducted in 5,354 primi- or secundigravidae in four West African countries with a low prevalence of resistance to SP (The Gambia, Mali, Burkina Faso and Ghana). Women in the IPTp-SP group received SP on two or three occasions whilst women in the ISTp group were screened two or three times with a RDT and treated if positive for malaria with artemether-lumefantrine (AL). ISTp-AL was non-inferior to IPTp-SP in preventing low birth weight (LBW), anemia and placental malaria, the primary trial endpoints. The prevalence of LBW was 15.1% and 15.6% in the IPTp-SP and ISTp-AL groups respectively (OR = 1.03 [95% CI: 0.88, 1.22]). The mean hemoglobin concentration at the last clinic attendance before delivery was 10.97g/dL and 10.94g/dL in the IPTp-SP and ISTp-AL groups respectively (mean difference: -0.03 g/dL [95% CI: -0.13, +0.06]). Active malaria infection of the placenta was found in 24.5% and in 24.2% of women in the IPTp-SP and ISTp-AL groups respectively (OR = 0.95 [95% CI 0.81, 1.12]). More women in the ISTp-AL than in the IPTp-SP group presented with malaria parasitemia between routine antenatal clinics (310 vs 182 episodes, rate difference: 49.4 per 1,000 pregnancies [95% CI 30.5, 68.3], but the number of hospital admissions for malaria was similar in the two groups.

CONCLUSIONS

Despite low levels of resistance to SP in the study areas, ISTp-AL performed as well as IPTp-SP. In the absence of an effective alternative medication to SP for IPTp, ISTp-AL is a potential alternative to IPTp in areas where SP resistance is high. It may also have a role in areas where malaria transmission is low and for the prevention of malaria in HIV positive women receiving cotrimoxazole prophylaxis in whom SP is contraindicated.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01084213 Pan African Clinical trials Registry PACT201202000272122.

The elimination of the onchocerciasis vector from the island of Bioko as a result of larviciding by the WHO African Programme for Onchocerciasis Control

The island of Bioko is part of the Republic of Equatorial Guinea and is the only island in the World to have endemic onchocerciasis. The disease is hyperendemic and shows a forest-type epidemiology with low levels of blindness and high levels of skin disease, and the whole population of 68,000 is estimated to be at risk. Control of onchocerciasis began in 1990 using ivermectin and this yielded significant clinical benefits but transmission was not interrupted. Feasibility and preparatory studies carried out between 1995 and 2002 confirmed the probable isolation of the vector on the island, the high vectorial efficiency of the Bioko form of Simulium yahense, the seasonality of river flow, blackfly breeding and biting densities, and the distribution of the vector breeding sites. It was proposed that larviciding should be carried out from January to April, when most of the island's rivers were dry or too low to support Simulium damnosum s.l., and that most rivers would not need to be treated above 500 m altitude because they were too small to support the breeding of S. damnosum s.l. Larviciding (with temephos) would need to be carried out by helicopter (because of problems of access by land), supplemented by ground-based delivery. Insecticide susceptibility trials showed that the Bioko form was highly susceptible to temephos, and insecticide carry was tested in the rivers by assessing the length of river in which S. damnosum s.l. larvae were killed below a temephos dosing point. Regular fly catching points were established in 1999 to provide pre-control biting densities, and to act as monitoring points for control efforts. An environmental impact assessment concluded that the proposed control programme could be expected to do little damage, and a large-scale larviciding trial using ground-based applications of temephos (Abate 20EC) throughout the northern (accessible) part of the island was carried out for five weeks from 12 February 2001. Following this, a first attempt to eliminate the vectors was conducted using helicopter and ground-based applications of temephos from February to May 2003, but this was not successful because some vector populations persisted and subsequently spread throughout the island. A second attempt from January to May 2005 aimed to treat all flowing watercourses and greatly increased the number of treatment points. This led to the successful elimination of the vector. The last biting S. damnosum s.l. was caught in March 2005 and none have been found since then for more than 3 years.

Identification of complement receptor one (CR1) polymorphisms in west Africa

Complement receptor one (CR1) is a ligand for the rosetting of Plasmodium falciparum infected red cells with uninfected cells. Since CR1 exhibits three known polymorphisms, we studied European-Americans (n = 112) and African-Americans (n = 330) and Malians (n = 158) to determine if genetic differences existed in an area endemic for malaria that could offer a survival advantage. The frequencies of Knops blood group phenotypes McC(b+) and Sl(a-) were greatly increased in Africans vs Europeans. Although the frequency of McC(b+) was similar between Africans from the USA or Mali, the Sl(a-) phenotype was significantly higher in Mali (39% vs 65%, respectively). There was an increased frequency of the largest size (250 kD) of CR1 in Mali, but this did not differ significantly from the USA (P = 0.09). Both cohorts of Africans had higher expression of red cell CR1 than European-Americans but this showed little difference between the USA and Mali groups. Thus, the most important CR1 polymorphism relevant to rosetting of malaria infected cells appears to be the Knops blood group.

A community effectiveness trial of strategies promoting intermittent preventive treatment with sulphadoxine-pyrimethamine in pregnant women in rural Burkina Faso

BACKGROUND

Intermittent preventive treatment with sulphadoxine-pyrimethamine for pregnant women (IPTp-SP) is currently being scaled up in many countries in sub-Saharan Africa. Despite high antenatal clinic (ANC) attendance, coverage with the required two doses of SP remains low. The study investigated whether a targeted community-based promotion campaign to increase ANC attendance and SP uptake could effectively improve pregnancy outcomes in the community.

METHODS

Between 2004 and 2006 twelve health centres in Boromo Health District, Burkina Faso were involved in this study. Four were strategically assigned to community promotion in addition to IPTp-SP (Intervention A) and eight were randomly allocated to either IPTp-SP (Intervention B) or weekly chloroquine (Control). Primi- and secundigravidae were enrolled at village level and thick films and packed cell volume (PCV) taken at 32 weeks gestation and at delivery. Placental smears were prepared and newborns weighed. Primary outcomes were peripheral parasitaemia during pregnancy and at delivery, placental malaria, maternal anaemia, mean and low birth weight. Secondary outcomes were the proportion of women with > or = 3 ANC visits and > or = 2 doses of SP. Intervention groups were compared using logistic and linear regression with linearized variance estimations to correct for the cluster-randomized design.

RESULTS

SP uptake (> or = 2 doses) was higher with (Intervention A: 70%) than without promotion (Intervention B: 49%) (OR 2.45 95%CI 1.25-4.82 p = 0.014). Peripheral (33.3%) and placental (30.3%) parasite rates were significantly higher in the control arm compared to Intervention B (peripheral: 20.1% OR 0.50 95%CI 0.37-0.69 p = 0.001; placental: 20.5% OR 0.59 95%CI 0.44-0.78 p = 0.002) but did not differ between Intervention A (17.4%; 18.1%) and Intervention B (20.1; 20.5%) (peripheral: OR 0.84 95%CI 0.60-1.18 p = 0.280; placental: OR 0.86 95%CI 0.58-1.29 p = 0.430). Mean PCV and birth weight and prevalence of anaemia and low birth weight did not differ between study arms.

CONCLUSION

The promotional campaign resulted in a major increase in IPTp-coverage, with two thirds of women at delivery having received > or = 2 SP. Despite lower prevalence of malaria infection this did not translate into a significant difference in maternal anaemia or birth weight. This data provides evidence that, as with immunization programmes, extremely high coverage is essential for effectiveness. This critical threshold of coverage needs to be defined, possibly on a regional basis.

Seasonal Dynamics of Malaria in Pregnancy in West Africa: Evidence for Carriage of Infections Acquired Before Pregnancy Until First Contact with Antenatal Care

In malaria-endemic areas, Plasmodium falciparum prevalence is often high in young women because of 1) low use of insecticide-treated nets before their first pregnancy and 2) acquired immunity, meaning infections are asymptomatic and thus untreated. Consequently, a common source of malaria in pregnancy (MiP) may be infected women becoming pregnant, rather than pregnant women becoming infected. In this study, prevalence of infection was determined by microscopy at first antenatal care (ANC) visit in primigravidae and secundigravidae in Ghana, Burkina Faso, Mali, and The Gambia, four countries with strong seasonal variations in transmission. Duration of pregnancy spent in the rainy season and other risk factors for infection were evaluated using multivariable Poisson regression. We found that the overall prevalence of malaria at first ANC was generally high and increased with time spent pregnant during the rainy season: prevalence among those with the longest exposure was 59.7% in Ghana, 56.7% in Burkina Faso, 42.2% in Mali, and 16.8% in Gambia. However, the prevalence was substantial even among women whose entire pregnancy before first ANC had occurred in the dry season: 41.3%, 34.4%, 11.5%, and 7.8%, respectively, in the four countries. In multivariable analysis, risk of infection was also higher among primigravidae, younger women, and those of lower socioeconomic status, independent of seasonality. High prevalence among women without exposure to high transmission during their pregnancy suggests that part of the MiP burden results from long-duration infections, including those acquired preconception. Prevention of malaria before pregnancy is needed to reduce the MiP burden.

Impact of long-term ivermectin (Mectizan) on Wuchereria bancrofti and Mansonella perstans infections in Burkina Faso: strategic and policy implications

Parasitological and clinical surveys were used to determine the long-term impact of ivermectin on the prevalence of Wuchereria bancrofti and Mansonella perstans filarial infections, when the drug was given under community-directed-treatment strategies for onchocerciasis control. The study was undertaken in 11 communities in south-western Burkina Faso. Six of the villages investigated had been treated with ivermectin at least once a year for five of 6 years, with a mean coverage of approximately 65% in each round. The other five, adjacent villages, which were matched with the ivermectin-treated communities by size, ethnicity and social and economic activities, had never been treated because they were not endemic for onchocerciasis. Each subject was checked by the microscopical examination of a smear of 'night' blood, by measurement of the level of circulating antigens from adult W. bancrofti, and by clinical examination for hydrocele (if male) and lymphoedema. The prevalences of lymphoedema and hydrocele in the treated villages were similar to those in the untreated. The prevalences and intensities of W. bancrofti and M. perstans microfilaraemia were, however, significantly lower in the ivermectin-treated communities. The implications of this study are discussed in relation to the old Onchocerciasis Control Programme (OCP) and to the ongoing African Programme for Onchocerciasis (APOC), where extensive and sustained ivermectin distribution is planned through community-based treatment programmes. As with onchocerciasis in Africa, the success of annual treatments to control lymphatic filariasis will depend not only on the number of regular rounds of treatment given but on adequate coverages being achieved in each round. Wherever ivermectin is being distributed alone, for onchocerciasis control, its impact on other filarial infections, notably W. bancrofti, should be evaluated routinely. Any opportunity to add donated albendazole to such distributions should be taken, both to limit the transmission of W. bancrofti and for the wider public-health benefits.

Implementation of the World Health Organization Regional Office for Africa Stepwise Laboratory Quality Improvement Process Towards Accreditation

Background

The increase in disease burden has continued to weigh upon health systems in Africa. The role of the laboratory has become increasingly critical in the improvement of health for diagnosis, management and treatment of diseases. In response, the World Health Organization Regional Office for Africa (WHO AFRO) and its partners created the WHO AFRO Stepwise Laboratory (Quality) Improvement Process Towards Accreditation (SLIPTA) program.

SLIPTA implementation process

WHO AFRO defined a governance structure with roles and responsibilities for six main stakeholders. Laboratories were evaluated by auditors trained and certified by the African Society for Laboratory Medicine. Laboratory performance was measured using the WHO AFRO SLIPTA scoring checklist and recognition certificates rated with 1–5 stars were issued.

Preliminary results

By March 2015, 27 of the 47 (57%) WHO AFRO member states had appointed a SLIPTA focal point and 14 Ministers of Health had endorsed SLIPTA as the desired programme for continuous quality improvement. Ninety-eight auditors from 17 African countries, competent in the Portuguese (3), French (12) and English (83) languages, were trained and certified. The mean score for the 159 laboratories audited between May 2013 and March 2015 was 69% (median 70%; SD 11.5; interquartile range 62–77). Of these audited laboratories, 70% achieved 55% compliance or higher (2 or more stars) and 1% scored at least 95% (5 stars). The lowest scoring sections of the WHO AFRO SLIPTA checklist were sections 6 (Internal Audit) and 10 (Corrective Action), which both had mean scores below 50%.

Conclusion

The WHO AFRO SLIPTA is a process that countries with limited resources can adopt for effective implementation of quality management systems. Political commitment, ownership and investment in continuous quality improvement are integral components of the process.

Human nerve growth factor beta (hNGF-beta): mammary gland specific expression and production in transgenic rabbits

Transgenic rabbits carrying gene constructs encoding human nerve growth factor beta (hNGF-beta) cDNA were generated. Expression of hNGF-beta mRNA was restricted to the mammary gland of lactating rabbits. Western Blot analysis revealed a polypeptide of 13.2 kDa in the milk of transgenic animals. hNGF-beta was purified from the milk by a two-step chromatographic procedure. Electrospray mass spectroscopy analysis of purified hNGF-beta depicted a molecular weight of 13,261 Da per subunit. The biological activity of the hNGF-beta was tested using PC12W2 cells and cultures of dorsal root ganglion neurons from chicken embryos. Crude defatted milk from transgenic animals and purified hNGF-beta demonstrated full biological activity when compared to commercial recombinant hNGF-beta.

Non-falciparum malaria infections in pregnant women in West Africa

BACKGROUND

Non-Plasmodium falciparum malaria infections are found in many parts of sub-Saharan Africa but little is known about their importance in pregnancy.

METHODS

Blood samples were collected at first antenatal clinic attendance from 2526 women enrolled in a trial of intermittent screening and treatment of malaria in pregnancy (ISTp) versus intermittent preventive treatment (IPTp) conducted in Burkina Faso, The Gambia, Ghana and Mali. DNA was extracted from blood spots and tested for P. falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale using a nested PCR test. Risk factors for a non-falciparum malaria infection were investigated and the influence of these infections on the outcome of pregnancy was determined.

RESULTS

P. falciparum infection was detected frequently (overall prevalence by PCR: 38.8 %, [95 % CI 37.0, 40.8]), with a prevalence ranging from 10.8 % in The Gambia to 56.1 % in Ghana. Non-falciparum malaria infections were found only rarely (overall prevalence 1.39 % [95 % CI 1.00, 1.92]), ranging from 0.17 % in the Gambia to 3.81 % in Mali. Ten non-falciparum mono-infections and 25 mixed falciparum and non-falciparum infections were found. P. malariae was the most frequent non-falciparum infection identified; P. vivax was detected only in Mali. Only four of the non-falciparum mono-infections were detected by microscopy or rapid diagnostic test. Recruitment during the late rainy season and low socio-economic status were associated with an increased risk of non-falciparum malaria as well as falciparum malaria. The outcome of pregnancy did not differ between women with a non-falciparum malaria infection and those who were not infected with malaria at first ANC attendance.

CONCLUSIONS

Non-falciparum infections were infrequent in the populations studied, rarely detected when present as a mono-infection and unlikely to have had an important impact on the outcome of pregnancy in the communities studied due to the small number of women infected with non-falciparum parasites.

Diagnostic quality in rural health centres in Burkina Faso

OBJECTIVE

To study the quality of diagnostic practice in rural Burkina Faso.

METHOD

In 9 health centres of 3 districts, 313 outpatient consultations were observed, and 417 diagnoses by 15 nurses were analysed. Criteria for evaluation of patient history and clinical examination were based on the diagnostic guidelines distributed by the Ministry of Health.

RESULTS

In only 20% of the diagnoses the nurses took a sufficient history and in only 40% they conducted a sufficient clinical examination. In 21% patients underwent no clinical examination at all. Only 12% of all diagnoses were based on sufficient history-taking and adequate clinical examinations. The individual elements of clinical examination were performed correctly in 82% of cases. The variation between nurses was immense, but no correlation could be found with regard to their basic training. However, nurses who had received the diagnostic guidelines examined patients more carefully than those who had not. Larger numbers of patients per day are not associated with shorter nurse-patient contact, and neither is sufficiency of patient history associated with duration of the consultation.

CONCLUSION

The low diagnostic quality of the outpatient consultations in the studied area indicates that this issue has been neglected in national public health initiatives. But examination skills are good and diagnostic guidelines may have had a positive effect on the diagnostic quality.

Chimera-type states induced by local coupling

Coupled oscillators can exhibit complex self-organization behavior such as phase turbulence, spatiotemporal intermittency, and chimera states. The latter corresponds to a coexistence of coherent and incoherent states apparently promoted by nonlocal or global coupling. Here we investigate the existence, stability properties, and bifurcation diagram of chimera-type states in a system with local coupling without different time scales. Based on a model of a chain of nonlinear oscillators coupled to adjacent neighbors, we identify the required attributes to observe these states: local coupling and bistability between a stationary and an oscillatory state close to a homoclinic bifurcation. The local coupling prevents the incoherent state from invading the coherent one, allowing concurrently the existence of a family of chimera states, which are organized by a homoclinic snaking bifurcation diagram.

Variation and phylogenetic utility of the Arabidopsis thaliana Rps2 homolog in various species of the tribe Brassiceae

Our objective was to analyze the evolutionary paths of cultivated diploid Brassica species and a few related wild species (tribe Brassiceae) in relation to Arabidopsis thaliana (tribe Arabidae), using the Rps2 sequence. Rps2 confers resistance to Pseudomonas syringae in A. thaliana. We found that similar to Arabidopsis, the Rps2 homolog in Brassica species is present in a single copy. Primers based in the Rps2 sequence amplified Rps2 homologs from the other species. Maximum-parsimony analysis based on number of nucleotide substitutions yielded a single tree, grouping the species as expected from other evolutionary inferences. Age of divergence between the two tribes was within the range of previous estimates. Indels in the different sequences were also useful for distinguishing some of the species. The Rps2 gene is a useful phylogenetic tool for more comprehensive studies of the species of Brasicaceae.

Chloroquine and sulphadoxine-pyrimethamine efficacy for uncomplicated malaria treatment and haematological recovery in children in Bobo-Dioulasso, Burkina Faso during a 3-year period 1998-2000

We determined the parasitological resistance and the clinical failure to chloroquine (CQ) and sulphadoxine-pyrimethamine (SP) by the WHO 14-day in vivo test over three consecutive years in 948 children aged 6-59 months with uncomplicated malaria attending four health centres in the province of Houet, Burkina Faso. Children were alternatively allocated to either CQ or SP. Packed cell volume (PCV) was measured at days 0 and 14. Parasitological resistance (RI, RII and RIII) to CQ was 18% (83 of 455) and to SP <1% (two of 308). Clinical failure with CQ was 12% (53 of 455) with no evidence of increase over time. Only one case of clinical failure was detected among the children treated with SP. The prevalence of anaemia (PCV <25%) was about 40% at day 0 and had decreased substantially by day 14 in both groups. However, in children treated with SP the prevalence of anaemia at day 14 was significantly lower than in those treated with CQ:RR = 3.15 (95% CI: 1.33-7.42, P = 0.008). CQ and SP are still efficacious for the treatment of uncomplicated malaria in children, at least in this area of Burkina Faso. However, the prevalences of CQ resistance reported from other areas of the country are worrying because of its potential spread. Regular surveillance of resistance to commonly used antimalarial drugs should continue.

Prevalence of blindness and visual impairment in the region of Ségou, Mali. A baseline survey for a primary eye care programme

A community-based cross-sectional study on the prevalence and causes of blindness and visual impairment was conducted between July and August 1990 in three rural districts in Ségou region, Mali. The study population consisted of 5871 villagers. In the study area, the overall prevalence of bilateral blindness was 1.7% (standardized rate for age 2.0% +/- 0.4%), of bilateral visual impairment 1.7% (2.1% +/- 0.4%), of unilateral blindness 1.7% (2.2% +/- 0.4%) and of unilateral visual impairment 1.0% (1.2 +/- 0.3%). No important differences were found between districts. Cataract was the most common cause of visual loss (54%) and was most prevalent among those over 50 years of age. In 43%, unilateral blindness was associated with trauma. Other major eye diseases accounting for high percentages of visual impairment were trachoma and glaucoma. Xerophthalmia appeared to be a major public health problem among children in the age group 0-5. It was concluded that blindness is a major public health problem in this region. Some recommendations are given for strengthening integrated primary eye care at the district level in Ségou region.

Expression and characterization of functional recombinant bovine follicle-stimulating hormone (boFSHalpha/beta) produced in the milk of transgenic rabbits

Bovine follicle-stimulating hormone (boFSH) is a heterodimeric glycoprotein that belongs to the pituitary gonadotropins. Bioactive FSH is composed of alpha and beta subunits which require extensive N-glycosylation and sialylation. The mammary gland of transgenic livestock is an attractive source for the synthesis of post-translationally modified proteins. Two mammary gland-specific gene constructs with the cDNA for the boFSH alpha (boFSHalpha) and beta (boFSHbeta) subunits controlled by bovine alpha-s1 casein regulatory sequences were co-microinjected into fertilized rabbit oocytes. Two FSHalpha/FSHbeta double transgenic rabbit lines were established. The transgene expression was strictly lactation and mammary gland specific. Protein analysis revealed the presence of the boFSH heterodimer in the milk of transgenic rabbits showing a molecular weight similar to that of purified pituitary gland derived boFSH (boFSH-P). Subunit specific antibodies detected both polypeptides with the expected molecular sizes. Biochemical characterization demonstrated the expected isoelectric points of the recombinant boFSH. The presence of the post-translationally added terminal sialic acid residues was indicated by wheat germ agglutinin (WGA) lectin Western blotting. The biological activity of the recombinant mammary gland produced boFSH was determined using a FSH-dependent reporter cell line. The bioactivity of the recombinant boFSH was comparable to that of purified boFSH-P.

Traditional couching is not an effective alternative procedure for cataract surgery in Mali

INTRODUCTION

In Mali, more cataract patients receive sight-restoring surgery using a traditional "couching" procedure (the lens inside the vitreous body) than by modern cataract surgery. In order to evaluate the relative effectiveness and other outcomes of the traditional procedure compared to the modern surgical intervention, we conducted a population-based survey in a rural district of Mali in 1996.

METHOD

A total of 99,800 persons from 160 villages were eligible to be included in the sample. All individuals operated for cataract by a modern procedure were checked for visual acuity and questioned regarding their clinical history, the cost of the surgery and their satisfaction with the surgery immediately following the operation and presently. Each patient was paired with one person operated by a traditional cataract surgical procedure.

RESULTS

From a total population of 99,800 we found 85 individuals (0.085%) who had been operated by intracapsular extraction (ICCE) without lens implantation and we paired these with 82 individuals operated by the traditional method and by a local healer. In both groups, males were predominant (74.4% in the modern group and 61.3% in the traditional) and the median age was 65 and 68 years, respectively. Men with a higher social status (defined as administrative or religious authority) were slightly more common among those operated by ICCE (18.9%) than among those operated by the traditional healer (4.4%). Nearly half (47.6%) of the patients operated by couching did not know that a modern alternative existed. The mean cost to the patient of the two procedures was similar; with traditional couching costing on average US$ 42.10 and modern surgery (including transport and drugs) costing US$ 52.40. The traditional healer was often paid partially in kind and the price paid varied according to the patient's ability to pay. The clinical results differed greatly between the two methods. After aphakic correction of eyes operated by ICCE, 5.3% had good vision (33/18), 76.8% had low vision (33/60 and <3/18) and 17.9% were still blind (<3/60). Of eyes operated by traditional couching, none had good vision, 29.1% had low vision and 70.9% were blind. The level of satisfaction was high (89.7%) among persons operated in an ophthalmic center by the modern method, and relatively low (22.6%) among persons operated traditionally.

DISCUSSION

In Mali, two types of providers offer two different interventions to treat cataract-blind persons. This study suggests that the couching method used by traditional healers is relatively expensive and ineffective. It is also potentially dangerous although this study did not address this question specifically. It is important that health policy makers and medical authorities do what they can to prevent traditional healers from performing the couching procedure, as well as informing the population about the existence of a more-effective and safer alternative. However, while more effective and safer, the results obtained by ICCE are not excellent either. Further, it is important to improve the quality of ophthalmic services in order to provide cataract patients with the best, most accessible and least expensive services possible.

Hereditary spastic paraplegia and amyotrophy associated with a novel locus on chromosome 19

We identified a family in Mali with two sisters affected by spastic paraplegia. In addition to spasticity and weakness of the lower limbs, the patients had marked atrophy of the distal upper extremities. Homozygosity mapping using single nucleotide polymorphism arrays showed that the sisters shared a region of extended homozygosity at chromosome 19p13.11-q12 that was not shared by controls. These findings indicate a clinically and genetically distinct form of hereditary spastic paraplegia with amyotrophy, designated SPG43.