Comparative evaluation of three histidine-rich Protein-2 based rapid diagnostic tests, microscopy and PCR for guiding malaria treatment in Ibadan, Southwest Nigeria.

BACKGROUND: Malaria rapid diagnostic tests (mRDTs) are the preferred option for programmatic deployment. AIMS: There are numerous mRDTs on the Nigerian market and there is a need to guide practitioners on the relative performance of the commonly used brands of mRDT in Nigeria. SUBJECTS AND METHODS: The performance of three commonly used Histidine-Rich-Protein-2-based mRDTs (SD-Bioline™, Carestart™ and Paracheck-Pf™) against microscopy of Giemsa stained blood and polymerase chain reaction (PCR) was evaluated among 190 febrile under-5 children in Ibadan, Nigeria. We calculated the sensitivity, specificity, predictive values, accuracy, and agreements. RESULTS: There were 53.2% males. The prevalence of malaria parasite by microscopy was 46.8% and 57.9% by PCR. Malaria parasite detection by SD-Bioline™ was 60.5%, Carestart™: 60.0% and Paracheck-Pf™ 60.0%. Using microscopy as the gold standard, the sensitivities of SD-Bioline™, Carestart™ and Paracheck-Pf™ mRDT were 97.8%, 96.7% and 97.8% respectively while the specificities were 73.0%, 72.0% and 74.0% respectively. Using PCR as the gold standard, the sensitivity for both SD-Bioline™ and Paracheck-Pf™ was 85.5% and for CareStart was 84.6% while the specificity of SD-Bioline™, Carestart™, and Paracheck-Pf™ was 73.8%, 72.4%, and 75.0% respectively. The test accuracy was 81.0% for both SD-Bioline™ and Paracheck-Pf™ and 80.0% for Caresatrt™. The kappa coefficient of agreement between PCR and each of SD-Bioline™, Carestart, ParaCheck™ and microscopy was 0.597, 0.578, 0.609 and 0.739 respectively. CONCLUSION: The performance of the three mRDTs is a proof that any of the three is suitable for use in the diagnosis of malaria in the southwest of Nigeria.

Cryptosporidium and other enteric parasitic infections in HIV-seropositive individuals with and without diarrhoea in Osogbo, Nigeria.

The primary objective of this cross-sectional study is to correlate the presence of Cryptosporidium and other gastrointestinal parasites with the presence of diarrhoea in human immunodeficiency virus (HIV)-infected patients. Stool samples from 96 HIV-seropositive cases were examined for non-opportunistic parasites using the direct and formol-ether concentration methods, while the modified Ziehl-Neelsen technique was used to detect Cryptosporidium spp. The overall prevalence of Cryptosporidium spp. was 54.2%. Other intestinal parasites detected included Ascaris lumbricoides (59.4%), hookworm (5.2%), Entamoeba histolytica (3.1%), Strongyloides stercoralis (1%) and Taenia spp. (1%). Infection inmales was more common (68.2%) than in females (55.4%) but the difference was not statistically significant. Therewas a significant association between Cryptosporidium infection and CD4+ count (P=0.0001), with the highest parasite prevalence (90%) observed among patients who had the lowest CD4+ count (<200 cells/mm3). Forty-five (86.5%) patients with Cryptosporidium infection presented with diarrhoea and the difference between those with and without diarrhoea was statistically significant (P=0.0001). There was a statistically significant difference (P=0.0001) among the age groups, with the 41-50 group showing the highest prevalence (84.6%) of infection. Co-infection was observed in 13.5% of the patients. As no drug is currently available for the treatment of cryptosporidiosis, emphasis should be placed on educating HIV-infected individuals about prevention.

Allelic diversity of merozoite surface protein 2 gene of P falciparum among children in Osogbo, Nigeria.

The genetic diversity of Plasmodium falciparum (P falciparum) infections in humans is implicated in the pathogenesis of malaria. This study provides the first estimate of the genetic diversity and genotype multiplicity of Plasmodium falciparum infection in children with uncomplicated P falciparum malaria in Osogbo, Nigeria. One hundred and one isolates were used for analysis of parasite population polymorphism and genotyped by nested-PCR of merozoite surface protein 2 (MSP2) block 3. Amplicons were obtained for all the 101 genotyped samples in MSP2 PCR with 9 alleles varying in size between 300 and 800 base pair. Thirty-three (31.7%) samples had FC27 allele while 27 (26.7%) had 3D7 allele and 35 (34.7%) had mixed alleles (3D7+FC27). The Multiplicity of Infection (MOI) in the population was 1.6. Children in the age group of > 4-8 years had the highest number of different genotypes in their samples (1.8). The number of MSP2 bands per isolate was lower in the older age group (1.3) but the difference was not statistically significant. Children with parasite density range 5001-10 000 had the highest MOI of 2 while those with parasite density range 1000-5000 had the lowest of 1.5. In conclusion, the present study shows that the field isolates are highly diverse in respect of MSP2 and multiplicity of infection was neither age nor parasite density dependent in the study population.

Lymphatic filariasis in a rural community in Nigeria: a challenge ahead.

Lymphatic filariasis (LF) represents a major public health problem in tropical and subtropical regions of the world. Following the admission of a 65 year old man from Sowo village Abeokuta Ogun State with a case of LF at the Federal Medical Centre Abeokuta, a cross-sectional based survey was carried out to determine the occurrence and prevalence of LF in this village. Identification of the LF parasite was carried out with blood stained with Giemsa and examined under low power magnification for the presence of sheathed microfilaria. Out of 317 persons examined 54 (17%) were microfilaraemic and their ages varied from 10 to 70 years. The age group 40-49 has the highest prevalence of 36.5% and highest mean microfilaria count of 4.8mf/mL. In the age group 20-29, females (12.8%) were more infected than males (9.3%) and the difference was statistically significant (P=0.0042). In all more males (17.8%) were affected than females (16.9%) (P=0.9481) and the mean MF count in males (22.8mf/ML) was higher than females (21.7mf/ML). The prevalent rate of elephantiasis and hydrecoele observed in the community was 2.2% respectively. The result of this study confirms and observed a high prevalence rate of LF in this community. This finding establishes the need for Ministry of Health (MOH) and Global Alliance to Eliminate LF (GAELF) to carry out disease control activities through Annual Mass Drug Administration (MDA) in this community.

Prevalence and transmission pattern of Plasmodium falciparum infection in Osogbo metropolis, southwest, Nigeria.

Plasmodium falciparum malaria is an endemic disease especially in tropical areas with heavy rainfall that spread round the year. We therefore sought to investigate the prevalence pattern and clinical presentation of falciparum malaria in Oso degrees c were assessed and screened for plasmodium falciparum infection by clinical assessment and microscopy using both thick and thin blood smears over a period of 12 months- August 2004 and July 2005. The prevalence of Plasmodium falciparum infection was found to be 52.8% with 341/646 of the patients been positive for Plasmodium falciparum parasite based on microscopy. Three hundred and five (47.2%) were aparasitaemic of which 162 (25.1%) had bronchopneumonia, 99 (15.3%) had upper respiratory tract infection, 32 (5.0%) had gastroenteritis and 12 (1.9%) had Otitis media. Between August and November 2004, 250 patients were screened and 160 (57.6%) of these patients were positive, while 180 patients were screened between December 2004 and March 2005 and 51 (28.3%) were positive. Between April 2005 and July 2005, 216 patients were screened and 130 (60.2%) of the patients were positive. When compared, the differences in the percentage of patients with positive microscopy in December to March with April to July and August to November were found to be significant (P < 0.0001), whereas the percentage difference in patients with positive microscopy in August to November and April to July was not significant (P = 0.442). The result of this study clearly shows that there are two distinct peaks of malaria transmission pattern in consonance with the rainfall pattern in the area.

Immunoglobulin classes (IgG, IgA and IgM) and acute phase proteins in pregnant women with urinary schistosomiasis.

BACKGROUND: S. haematobium have been implicated in female genital schistosomiasis (FGS), ectopic pregnancy and infertility. The presence of schistosome eggs in urine has been reported to correlate with FGS but host immune response in FGS is yet to be determined. This gap in knowledge is addressed by this study. MATERIALS AND METHODS: Serum levels of three immunoglobulin classes (IgG, IgA and IgM) and three acute phase proteins (transferrin, alpha 2-macroglobulin, and haptoglobin) were determined by using single radial immunodiffusion technique in one hundred and eight Nigerian women aged between 15 and 30 years. They were made up of thirty pregnant women with urinary schistosomiasis (P+USS), thirty-six pregnant women without USS (P-USS), eighteen non-pregnant women with USS (NP+USS) and twenty-four healthy non-pregnant women without urinary schistosomiasis (NP-USS). RESULTS AND CONCLUSIONS: IgG, IgA and IgM were significantly raised in pregnant women with urinary schistosomiasis compared with non-pregnant women without urinary schistosomiasis (p < 0.01 in each case). The level of transferrin was significantly increased in non-pregnant subjects with urinary schistosomiasis compared with non-pregnant women without urinary schistosomiasis (p <0.01) suggesting the possibility of iron deficiency in these subjects. Alpha-2 macroglobulin was significantly elevated in pregnant subjects with urinary schistosomiasis compared with non-USS subjects, while the mean serum haptoglobin level was significantly higher in pregnant women without urinary schistosomiasis compared to pregnant subjects with urinary schistosomiasis. The results indicate that USS or pregnancy changes different aspects of humoral immunity, thus the co-existence of pregnancy and S. haematobium infection may influence each other.

In vivo Antimalarial Activities of Russelia Equisetiformis in Plasmodium Berghei Infected Mice.

The rising problem of resistance to most commonly used antimalarials remains a major challenge in the control of malaria suggesting the need for new antimalarial agents. This work explores the antiplasmodial potential of ethanol extract of Russelia equisetiformis in chloroquine Plasmodium berghei infected mice. Swiss albino mice were intraperitoneally infected with chloroquine-resistant P. berghei (ANKA). Experimental mice were treated for four days consecutively with graded doses of plant extracts and standard antimalarial drugs (artesunate and chloroquine) at a dose of 10 mg/kg body weight used as control. The extract showed a dose-dependent activity in the chemosuppression of P. berghei parasites by 31.6, 44.7, 48.4 and 86.5% at doses of 100, 200, 400 and 800 mg/kg, while chloroquine (10 mg/kg) and artesunate produced 59.4 and 68.4%, respectively. The extract showed a significant decrease in parasitaemia (P<0.05). The level of parasitemia and decrease in weight in all the treated groups was significantly lower (P<0.05) compared with the infected but untreated mice. The plant extract was devoid of toxicity at the highest dose tested (5000 mg/kg). The study concluded that the ethanol extract of R. equisetiformis possesses antimalarial effect, which supports the folk medicine claim of its use in the treatment of malaria.

Chloroquine resistant Plasmodium falciparum malaria in Osogbo Nigeria: efficacy of amodiaquine + sulfadoxine-pyrimethamine and chloroquine + chlorpheniramine for treatment.

Chloroquine (CQ) resistance in Plasmodium falciparum contributes to increasing malaria-attributable morbidity and mortality in Sub-Saharan Africa. Despite a change in drug policy, continued prescription of CQ did not abate. Therefore the therapeutic efficacy of CQ in uncomplicated falciparum malaria patients was assessed in a standard 28-day protocol in 116 children aged between six and 120 months in Osogbo, Southwest Nigeria. Parasitological and clinical assessments of response to treatment showed that 72 (62.1%) of the patients were cured and 44 (37.9%) failed the CQ treatment. High initial parasite density and young age were independent predictors for early treatment failure. Out of the 44 patients that failed CQ, 24 received amodiaquine + sulphadoxine/pyrimethamine (AQ+SP) and 20 received chlorpheniramine + chloroquine (CH+CQ) combinations. Mean fever clearance time in those treated with AQ+SP was not significantly different from those treated with CH+CQ (p = 0.05). There was no significant difference in the mean parasite density of the two groups. The cure rate for AQ+SP group was 92% while those of CH+CQ was 85%. There was a significant difference in parasite clearance time (p = 0.01) between the two groups. The 38% treatment failure for CQ reported in this study is higher than the 10% recommended by World Health Organization in other to effect change in antimalarial treatment policy. Hence we conclude that CQ can no more be solely relied upon for the treatment of falciparum malaria in Osogbo, Nigeria. AQ+SP and CH+CQ are effective in the treatment of acute uncomplicated malaria and may be considered as useful alternative drugs in the absence of artemisinin-based combination therapies.

Allelic diversity of merozoite surface protein 2 gene of P falciparum among children in Osogbo, Nigeria / Diversidad alélica del gen de la proteína de superficie del merozoíto 2 del P falciparum entre los niños de Osogobo, en Nigeria

The genetic diversity of Plasmodium falciparum (P falciparum) infections in humans is implicated in the pathogenesis of malaria. This study provides the first estimate of the genetic diversity and genotype multiplicity of Plasmodium falciparum infection in children with uncomplicated P falciparum malaria in Osogbo, Nigeria. One hundred and one isolates were used for analysis of parasite population polymorphism and genotyped by nested-PCR of merozoite surface protein 2 (MSP2) block 3. Amplicons were obtained for all the 101 genotyped samples in MSP2 PCR with 9 alleles varying in size between 300 and 800 base pair. Thirty-three (31.7%) samples had FC27 allele while 27 (26.7%) had 3D7 allele and 35 (34.7%) had mixed alleles (3D7+FC27). The Multiplicity of Infection (MOI) in the population was 1.6. Children in the age group of > 4-8 years had the highest number of different genotypes in their samples (1.8). The number of MSP2 bands per isolate was lower in the older age group (1.3) but the difference was not statistically significant. Children with parasite density range 5001-10 000 had the highest MOI of 2 while those with parasite density range 1000-5000 had the lowest of1.5. In conclusion, the present study shows that the field isolates are highly diverse in respect ofMSP2 and multiplicity of infection was neither age nor parasite density dependent in the study population.

La diversidad genética de las infecciones por Plasmodium falciparum en los humanos se halla implícita en la patogénesis de la malaria. Este estudio proporciona un primer estimado de la diversidad genética y multiplicidad del genotipo de la infección por Plasmodium falciparum en los niños con malaria por P falciparum malaria sin complicaciones en Osogbo, Nigeria. Ciento un aislados fueron usados para el análisis del polimorfismo de la población parasitaria, y genotipificados mediante reacción en cadena de la polimerasa (RCP) anidada de la proteína de superficie del merozoíto 2 (MSP2) bloque 3. Se obtuvieron amplicones para las 101 muestras genotipificadas con RCP de MSP2, con 9 alelos variando en tamaño entre 300 y 800 par de bases. Treinta y tres (31.7%) muestras tenían el alelo FC27 mientras 27 (26.7%) tenían el alelo 3D7 y 35 (34.7%) tenían alelos mezclado (3D7+FC27). La multiplicidad de infección (MOI) en la población fue 1.6. Los niños en el grupo etario de > 4-8 años tenían el número más alto de genotipos diferentes en sus muestras (1.8). El número de bandas de MSP2 por aislado era más bajo en el grupo etario de mayor edad (1.3) pero la diferencia no era estadísticamente significativa. Los niños con un rango de densidad parasitaria 5001-10 000 tenían el MOI más alto equivalente a 2, mientras aquéllos con rango de densidad parasitaria 1000-5000 tenían el MOI más bajo equivalente a 1.5. En conclusión, el presente estudio muestra que los aislados de campo son altamente diversos con respecto al MSP2, y que la multiplicidad de la infección no depende ni de la edad ni de la densidad parasitaria de la población en estudio.

Chloroquine resistant Plasmodium falciparum malaria in Osogbo Nigeria: efficacy of amodiaquine + sulfadoxine-pyrimethamine and chloroquine + chlorpheniramine for treatment

Chloroquine (CQ) resistance in Plasmodium falciparum contributes to increasing malaria-attributable morbidity and mortality in Sub-Saharan Africa. Despite a change in drug policy, continued prescription of CQ did not abate. Therefore the therapeutic efficacy of CQ in uncomplicated falciparum malaria patients was assessed in a standard 28-day protocol in 116 children aged between six and 120 months in Osogbo, Southwest Nigeria. Parasitological and clinical assessments of response to treatment showed that 72 (62.1 percent) of the patients were cured and 44 (37.9 percent) failed the CQ treatment. High initial parasite density and young age were independent predictors for early treatment failure. Out of the 44 patients that failed CQ, 24 received amodiaquine + sulphadoxine/pyrimethamine (AQ+SP) and 20 received chlorpheniramine + chloroquine (CH+CQ) combinations. Mean fever clearance time in those treated with AQ+SP was not significantly different from those treated with CH+CQ (p = 0.05). There was no significant difference in the mean parasite density of the two groups. The cure rate for AQ+SP group was 92 percent while those of CH+CQ was 85 percent. There was a significant difference in parasite clearance time (p = 0.01) between the two groups. The 38 percent treatment failure for CQ reported in this study is higher than the 10 percent recommended by World Health Organization in other to effect change in antimalarial treatment policy. Hence we conclude that CQ can no more be solely relied upon for the treatment of falciparum malaria in Osogbo, Nigeria. AQ+SP and CH+CQ are effective in the treatment of acute uncomplicated malaria and may be considered as useful alternative drugs in the absence of artemisinin-based combination therapies.