Evaluation of the sensitivity and specificity of rapid human immunodeficiency virus (HIV)1 and 2 test kits commonly used in Nigeria

The sensitivity and specificity of five rapid HIV antibody test kits commonly used in Nigeria were evaluated. The kits were selected based on their high percentage frequency of use as compared to others. A total of 100 EIA HIV-1and RNA HIV-1 positive sera were used as positive gold standard; while 100 EIA HIV-1 and RNA HIV-1 negative sera were used as negative gold standard. The positive gold standard sera were pooled; serially diluted and analysed to determine the sensitivities of the kits. The methods used were strictly as provided by the manufacturers. Of the 100 positive gold standard serum samples used; Immunocomb-II gave false negative results with 10 (Sensitivity = 90); while HIV-SAV; Hexagon; Determine and SD-Bioline were false negative with 12 specimens; representing 88 sensitivity for each. On the other hand; of the 100 negative gold standard sera; Immunocomb-II gave 6 false positive results (Specificity = 94); HIV-SAV 12 (Specificity = 88); Hexagon 2 (Specificity = 98); Determine 12 (Specificity = 88); while SD-Bioline had no false positive result (specificity = 100). In analytical sensitivity; Immunocomb-II detected the highest serum titre of 30 000; making it the most sensitive. Two of the five test kits (Immunocomb and SD-Bioline) demonstrated excellent analytical sensitivity and specificity respectively. The two could be recommended for use as combination test algorithms instead of EIA/Western Blot algorithm; which is time-consuming; expensive and often not technically feasible in a developing country like ours. This study shows that not all the analytical performance indices cited in the literature from the manufacturers of diagnostic kits are necessarily reproducible in end-user laboratories

Prevalence of Lassa virus among rodents trapped in three South-South States of Nigeria.

BACKGROUND & OBJECTIVES: Lassa fever has been endemic in Nigeria since 1969. The rodent Mastomys natalensis has been widely claimed to be the reservoir host of the Lassa virus. This study was designed to investigate the dis- tribution of species of rodents in three states (Edo, Delta and Bayelsa) of Nigeria and to determine the prevalence of Lassa virus amongst trapped rodents in the selected states. METHODS: Rodents were trapped during November 2015 to October 2016 from the three states in South-South re- gion of Nigeria. Total RNA was extracted from the blood collected from the trapped rodents. Reverse transcription polymerase chain reaction (RT-PCR) was used to confirm the presence of Lassa virus in the rodents. RESULTS: The results revealed that six species of rodents were predominantly present in these geographical locations. Mus musculus (39.4%) had the highest prevalence, closely followed by Rattus rattus (36.1%), R. fuscipus (20.3%), M. natalensis (2%), Myosoricinae soricidae (1.2%) and R. norvegicus (1%). The overall positivity (carrier rate) of Lassa virus was 1.6% amongst the 1500 rodents caught in the three states. In Edo and Delta States, the RT-PCR results showed presence of Lassa virus in R. rattus, M. musculus and M. natalensis. On the other hand, only M. na- talensis was detected with the virus, amongst the species of rodents caught in Bayelsa State. M. natalensis recorded the highest Lassa virus among rodents trapped in Edo (87%), Delta (50%) and Bayelsa (11%) States respectively. INTERPRETATION & CONCLUSION: The rather low Lassa virus positive among rodents in Bayelsa State of Nigeria may explain the absence of reports of outbreak of Lassa fever over the past 48 yr in the state. The results also confirmed that apart from Mastomys natalensis, other rodents such as Rattus rattus and Mus musculus may also serve as res- ervoirs for Lassa virus. From the findings of this cross-sectional study, it was concluded that a more comprehensive study on rodents as reservoir host, need to be undertaken across the entire states of Nigeria, for better understanding of the epidemiology and endemicity of Lassa fever.

Measurement of Th1, Th2 cytokines and white cell count in childhood haemoglobinopathies with uncomplicated malaria infection.

BACKGROUND/OBJECTIVE: The relative balance between Th1 and Th2 cytokines appears crucial in the outcome of infections. We assayed the levels of some proinflammatory Th1 cytokines, interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), and anti-inflammatory Th2 cytokines, IL-4 and IL-10 in homozygous haemoglobin (Hb) AA, heterozygous HbAS-genotyped and sickle cell (HbSS) individuals with uncomplicated Plasmodium falciparum malaria. METHODS: Levels of Th1 and Th2 cytokines of 111 children aged 1-5 years with uncomplicated malaria and 89 healthy controls were determined by enzyme linked immunosorbent assay and haematological parameters were estimated using the automated Swelab counter (Boule Medical, Stockholm, Sweden). RESULTS: Th1 and Th2 cytokine levels were significantly higher in HbAA and HbAS-genotyped patients compared to their respective healthy controls (P<0·05). IFN-gamma, IL-2, and IL-10 were significantly elevated in HbAA compared to HbAS and HbSS subjects (P<0·05). The mean haematological parameters (total white cell count and monocytes) of HbSS-infected children were significantly higher compared to those of HbAA and HbAS subjects (P<0·05); however, their mean packed cell volume was significantly lower compared to others (P<0·05). CONCLUSION: Our results showed a stronger Th1 cytokine response in HbAA than HbAS and HbSS individuals; this may suggest an immunocompetence of the HbAA individuals in early infection.

Chloroquine prophylaxis associated with high prevalence of Plasmodium falciparum pfcrt K76T mutation in people with sickle-cell disease in Benin City, Nigeria.

BACKGROUND & OBJECTIVES: High mortality and morbidity in sickle-cell disease has been associated with malaria infection especially in countries where chloroquine is used. Chloroquine resistance has been associated with the emergence of Pfcrt mutant genes. This study aimed at comparing the prevalence rate of Pfcrt T76 mutation in Plasmodium falciparum isolates from infected individuals with sickle-cell disease and sickle-cell trait. This study was carried out in Benin City between the months of April and June 2006. This period is marked with high transmission rate of malaria. METHODS: The genotype of the subjects was screened using haemoglobin electrophoresis system and the P. falciparum. Pfcrt genotyping was carried out using PCR-restriction fragment length polymorphism (RFLP). RESULTS: Four hundred and twenty-four subjects comprising of 207 haemoglobin AA, 136 haemoglobin AS and 81 haemoglobin SS typed individuals were enrolled for this study. No significant difference existed in the prevalence rate of malaria in the three groups (p > 0.05). However, the prevalence rate of Pfcrt K76T mutant gene was higher in the haemoglobin SS genotyped individuals than the haemoglobin AA and AS subjects (p < 0.05). INTERPRETATION & CONCLUSION: An uncontrolled use of chloroquine has been incriminated as the major cause of chloroquine resistance in Nigeria. Therefore, rapid intervention measures are needed as a matter of urgency to curb the up rise in the prevalence of the chloroquine resistant genes in our environment.

Prevalence of chlamydia in patients attending gynecological clinics in south eastern Nigeria.

BACKGROUND: Chlamydia infections have been reported to cause silent infections in communities which becomes endemic and could remain unnoticed for a very long time. In most parts of Nigeria these organisms are not screened for, and hence relative information about frequencies of the organisms are sparse. METHOD: Five hundred and sixty five blood samples and ten umbilical cord fluids were collected from various patients attending clinics in South Eastern Nigeria and were screened for Chlamydia Complement Fixing Antibody (CCFA). Endocervical swabs and urethral discharges or swabs were collected from patients whose serum was positive and were cultured into embryonic eggs which was later observed, harvested and stained using the Romanowsky-Giemsa staining techniques. The positive sera were further confirmed by distinguishing the species of Chlamydia using the monoclonal antibody spot test kit. RESULT: Of the five hundred and sixty five (565) samples collected only three hundred and forty were positive to CCFA, of which 141 were males and 204 females. From the cultured samples 230 were positive for Chlamydia trachomatis and 99 positive to Chlamydia pneumoniae. Statistical analysis using the student's t test at 95% confidence interval shows that there was no significant difference between the number of females and males that presented themselves for screening. CONCLUSION: Proper screening of patients to include Chlamydia should be encouraged at all levels of medical diagnosis in the country so as to proffer treatment. Otherwise the infection will remain a "silent epidemic", as is the case currently.

Prevalence of Chlamydia in Patients Attending Gynecological Clinics in South Eastern Nigeria

"Background: Chlamydia infections have been reported to cause silent infections in communities which becomes endemic and could remain unnoticed for a very long time. In most parts of Nigeria these organisms are not screened for; and hence relative information about frequencies of the organisms are sparse. Method: Five hundred and sixty five blood samples and ten umbilical cord fluids were collected from various patients attending clinics in South Eastern Nigeria and were screened for Chlamydia Complement Fixing Antibody (CCFA). Endocervical swabs and urethral discharges or swabs were collected from patients whose serum was positive and were cultured into embryonic eggs which was later observed; harvested and stained using the Romanowsky - Giemsa staining techniques. The positive sera were further confirmed by distinguishing the species of Chlamydia using the monoclonal antibody spot test kit. Result: Of the five hundred and sixty five (565) samples collected only three hundred and forty were positive to CCFA; of which 141 were males and 204 females. From the cultured samples 230 were positive for Chlamydia trachomatis and 99 positive to Chlamydia pneumoniae. Statistical analysis using the student's t test at 95confidence interval shows that there was no significant difference between the number of females and males that presented themselves for screening. Conclusion: Proper screening of patients to include Chlamydia should be encouraged at all levels of medical diagnosis in the country so as to proffer treatment. Otherwise the infection will remain a ""silent epidemic""; as is the case currently."

Lassa virus: seroepidemiological survey of rodents caught in Ekpoma and environs.

Of the 876 rodents caught in different parts of Ekpoma, Nigeria, and environs, 218 were Mastomys natalensis, while 658 were other rodents. Of the 218 M. natalensis caught, 102 (46.79%) were positive for complement fixing antibody to Lassa virus.

Diagnosis and Management of Chancroid in Nigeria.

There is a broad group of venereal disease that is referred to as the "Tropical Venereal Disease". They are so-called because they are most frequently seen in the tropical and sub-tropical areas of the world. Among them are conditions like chancroid, lymphogranuloma venereum (LGV or climatic bubo) and granuloma inguinale (chronic venereal sores). Chancroid is variously called "soft sore" or "soft chancre" because it bleeds easily and "ulcus moile".1 It is an acute infection and auto-innoculable disease. The extent of chancroid genital ulceration in Nigeria is greater in the Northern partly due to permissive sexual practices especially for men.

Effects of anti-protozoal drugs and histopathological studies on trypanosome species.

The trypanosomostatic and trypanosomicidal effects of four anti-protozoal drugs, namely halofantrine hydrochloride, chloroquine phosphate, benzoylmetronidazole and pyrimethamine, on species of trypanosomes, viz. Trypanosoma brucei brucei (MBOS/NG/94/NITR) Bassa strain, T. congolense (MBOS/NG/93/NVRI) Zaria strain and T. brucei gambiense (MHOM/NG/92/NITR) Abraka strain, were investigated. In vitro and in vivo studies on these drugs vis-a-vis the parasites were carried out. The histopathological changes in organs and tissues of experimentally infected rats were also studied. Results from the in vitro studies indicated that halofantrine hydrochloride, chloroquine phosphate, benzoylmetronidazole and pyrimethamine appeared to be effective trypanosomicidal agents against T. brucei brucei (Bassa strain), T. congolense (Zaria strain) and T. brucei gambiense (Abraka strain). The in vivo studies showed that these drugs were sub-curative by prolonging the survival period of the trypanosome-infected rats, but not necessarily curing the infection. Histopathological findings indicated inflammatory reactions characterised by infiltration to variable degrees in the majority of tissues, mostly in the lungs and liver. The most consistent lesions were interstitial pneumonia, multifocal necrosis and oedema. Pathological findings showed the T. brucei brucei and T. brucei gambiense strains studied to be both intravascular and extravascular parasites. These results suggest that halofantrine hydrochloride, chloroquine phosphate, benzoylmetronidazole and pyrimethamine could be used as supportive, suppressive and/or synergistic/additive drugs in the treatment of African trypanosomiasis. Their effects on species of trypanosomes have been studied and are reported for the first time.

Preliminary investigation on aflatoxin in cord blood of jaundiced neonates.

Cord blood was obtained from 164 neonates at birth and investigated for the presence of aflatoxins. 14 of the samples were neonates without jaundice and 150 from neonates with jaundice. There was significant reduction (P > 0.05) in birth weight of jaundiced neonates with aflatoxin. Neonates with jaundice have high mean concentration of aflatoxin B1 (32.3 ng/ml and 35.6 ng/ml). Aflatoxin G1 was not detected in any of the groups. The rate of detection was higher in wet (81.8%) than dry season (50.0%). These findings show that neonates are exposed to aflatoxin prenatally and that high incidence of jaundice occurred in the wet warm months.

Euphorbia hirta leaves and Musa sapientum fruits in culture media for fungi.

Two plant products, Euphorbia hirta leaves and fruits of Musa sapientum, were evaluated as principal ingredients for selective cultivation of fungi. Sapientum glucose agar supported the growth of both dermatophytic, yeast-like, and saprophytic fungi; growth on this medium compared favourably with growth on Sabouraud glucose agar, a standard mycological medium. Sporulation and pigment formation were stronger on sapientum glucose agar than on Sabouraud glucose agar, although fungal growth on the latter was more luxuriant. Addition of Euphorbia extract to mycological media remarkably enhanced fungal growth on the media, and concomitantly suppressed bacterial growth to a similar extent as did antibiotics. The results of this study suggest that Euphorbia sapientum glucose agar can safely be recommended as a cheap and efficient medium for routine isolation of fungi in both clinical and general mycological studies.

Adherence of Candida albicans to human vaginal epithelial cells.

The adherence capacity of Candida species to female vaginal epithelial cells was examined. The results showed that in four groups of patients studied, the highest adherence was with epithelial cells collected from pregnant diabetic women (47% adherence, and 1,700 adherent yeasts). Pregnant or diabetic women had 39% each of adherence to epithelial cells but differed in the number of adherent yeasts (1,400 and 1,000 respectively). The diabetic and pregnant women therefore appeared differential attachment to epithelial cells from different physiologically adapted women.

Importance of anti-Plesiomonas antibody in the protection of rats against infection by Plesiomonas Shigelloides.

Rabbit anti-antibody raised against Plesiomonas shigelloides infections using standard immunological procedures. Ten (50%) of 20 rats died when only P. shigelloidess was injected while 2(10%) died [P < 0.05]; following injection of another group of 20 rats with P. shigelloides 24hours after administration of rabbit-Plesiomonas anti-antibody. In another scheme, 14(70%) of 20 rats died when p.shigelloides and colloidal carbon particles (CCP) were administered while only 4(20%) died (p<0.05) following injection of P. shigelloides and CCP 24 hours after administration of rabbit-Plesiomonas anti-antibody. No death was recorded for control rats which received only CCP. This study highlights a novel approach in the management or prevention of P. shigelloides infection in our environment.

Dermatophytosis in schoolchildren in Ekpoma, Nigeria.

Of 1400 pupils from two public primary schools in Ekpoma, Edo State, Nigeria, who were screened for dermatophyte infection, 188 (13.4%) were infected. The causative agents isolated included Microsporum audouinii in 88 (46.8%), Trichophyton mentagrophytes in 48 (25.5%), T. rubrum in 40 (21.3%), T. tonsurans in four (2.1%) and Epidermophyton floccosum in eight (4.3%). There were significant differences in the rate of infection between male and female schoolchildren as well as between children from different socioeconomic backgrounds.

Anti-Plesiomonas shigelloides agglutinating and complement-fixing antibody titres in normal individuals and diarrhoeal patients in Edo State, Nigeria.

One hundred patients with diarrhoea and 50 asymptomatic individuals attending various hospitals in Edo State, Nigeria, were screened for serum complement-fixing and agglutinating antibodies to Plesiomonas shigelloides using the complement-fixation and agglutination tests. Seventy (70%) of the 100 patients and 20 (40%) of the 50 asymptomatic individuals had detectable complement-fixing antibodies at titres ranging from 1:32 to 1:128 and 1:8 to 1:32 respectively. Results suggest that cases of diarrhoea in this environment may be due to P. shigelloides, but the demonstration of antibodies in asymptomatic individuals show that they also have serum antibodies against P. shigelloides. The exclusive use of antibody responses in the diagnosis of P. shigelloides infections should, therefore, be interpreted with caution.

Carriage of Yersinia species by snails (Achachatina marginata): an epidemiological survey.

Three Yersinia species Yersinia enterocolitica, serogroup 0:9, Yersinia intermedia, serogroup 0:52.54 and Yersinia fredricksenii, serogroup 0:44.45 were experimentally inoculated into 249 giant African snails, Achachatina marginata, and the rate of recovery, as well as change (loss or gain) in weight determined. Results obtained showed that there was a high recovery rate of the inoculated Yersinia serogroups. Also, the snails showed loss in weight which increased with increase in recovery rate. No death of the infected snail was recorded. This study has revealed that snails (Achachatina marginata) could be potential carriers of Yersinia spp. and may therefore, play a role in the epidemiology of yersiniosis in our environment.

Evaluation of the pathogenicity and virulence of Yersinia species isolated in Edo and Delta States of Nigeria.

Sixteen isolates of four species of Yersinia comprising five of Yersinia enterocolitica and Yersinia fredricksenii, four of Yersinia intermedia and two of Yersinia kristensenii isolated from domestic and wild animals in villages in Edo and Delta States, Nigeria, were evaluated for their pathogenicity using laboratory animal models and virulence characteristics tests which included autoagglutinability, calcium dependency for growth, heat-stable enterotoxin production and conjunctivities in guinea pig eye. Results obtained revealed that Yersinia enterocolitica isolates were enteropathogenic as demonstrated by the production of diarrhoea and eventual recovery from faeces, spleen and liver of the infected animals. Three (60%) (2 serotypes 0:3 and 1 serotype 0:8) of the five Yersinia enterocolitica isolates were lethal to the animals. Other Yersinia isolates (Yersinia kristensenii, Yersinia fredricksenii and Yersinia intermedia) were uniformly non pathogenic to the animals. However, a strain of Yersinia intermedia isolate produced diarrhoea in the inoculated animals and caused lethality in guinea pigs and mice, but was negative for autoagglutination test, calcium dependency, conjunctivities, and positive for heat-stable enterotoxin production. We are of the view that this strain may be another Yersinia intermedia--like bacterium, previously isolated in Nigeria. Results therefore, suggest an emergence of a pathogenic Yersinia intermedia species in this environment.

A comparison of human immunodeficiency virus (HIV) seropositivity and hepatitis B surface antigenemia (HBs Ag) among the same group of apparently healthy pregnant women in Lagos, Nigeria: a preliminary report.

Two hundred and fifty apparently healthy pregnant women attending the Obstetrics and Gynecology Clinic of the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria were screened for a comparison of the prevalence of HIV seropositivity and hepatitis B surface antigenemia (HBs Ag) amongst them. The Karpas AIDS cell test for HIV seropositivity and Bioman Hepatitis test kits were used as described by the manufacturers. HIV seropositive cases were confirmed using the Western blot test. Results revealed that out of the 250 pregnant women screened, 2 (0.8%) and 11 (4.4%) were HIV-1 and HBs Ag seropositive, respectively. However, the same 2 pregnant women now constituting 2 (18.2%) of the 11 HBs Ag positive pregnant women were simultaneously HIV-1 seropositive. Antibody to HIV-2 was not recorded in all HIV seropositive cases. This is the first report on the simultaneous prevalence of HBs Ag and HIV seropositivity among apparently healthy pregnant women in Lagos, Nigeria.

PIP: 250 sperm from apparently healthy pregnant patients at the Obstetrics and Gynecology Clinic at Lagos University Teaching Hospital, Lagos, Nigeria, were tested for HIV-1 and HIV-2 and hepatitis B surface antigen (HBsAg). Sera were screened for HIV with the Karpas AIDS cell test using HIV-1 and HIV-2 isolated in Great Britain, and confirmed with the Karpas confirming test and the Western blot. Bioman Hepatek kits were used for hepatitis screening. 2 pregnant women (0.8%) tested positive for HIV-1 and none for HIV-2. 11 women (4.4%) had HBsAg in their serum, and among these, 2 were positive for both HBsAg and HIV-1. This is the first report of pregnant women with both HIV and hepatitis virus screens in Lagos.