Polymorphism analysis of drug resistance markers in Plasmodium falciparum isolates from Benin.

Like most countries in sub-Saharan African countries, Benin continues to bear a heavy malaria burden. In 2014, the National Malaria Control Programme (NMCP) changed its treatment policy, and recommended the use of artemisinin-based combination therapy (ACT) as first-line treatment for uncomplicated Plasmodium falciparum cases. The study presented here was conducted to investigate the impact of current antimalarial drug resistance on the country. Molecular surveillance targeting the Pfcrt, Pfmdr1, Pfkelch13, dhfr, and dhps genes was carried out on samples from patients positive for P. falciparum malaria by microscopy, LAMP and PCR diagnostic test. Molecular analysis was performed using targeted amplicon deep sequencing (TADS). In addition, the frequency of parasites with dual deletion of the histidine-rich protein 2 and 3 genes (pfhrp2 and pfhrp3), known to be responsible of the performance of HRP-based malaria rapid diagnostic tests (HRP-RDT), was estimated. Fifty-three falciparum samples collected at the Saint Jean de Dieu hospital in Tanguiéta, Benin, were tested. No Pfkelch13 validated or candidate artemisinin partial resistant variants were identified. A marked prevalence of Asn51Ile (N51I), Cys59Arg (C59R), and Ser108Asn (S108N) mutant alleles was found in the dhfr gene, representing the most frequent genotype (64%). Five-point mutations were detected in dhps, Ile431Val (I431V), Ser436Ala (S436A), Ala437Gly (A437G), Ala581Gly (A581G), Ala613Ser (A613S) of which the third was the most common (92%). No mutation was identified in dhps Lys540Glu (K540E). The quintuple mutant genotype resulting from the combination of the dhfr triple mutant (51I/59R/108N) with the dhps double mutant 436A/437G was detected at a frequency of 30%. Low levels of mutations in Pfcrt and no mutation at codon 86 in the Pfmdr1 DNA fragment were observed, whereas a high level of Tyr184Phe (Y184F) polymorphism in the Pfmdr1 gene was found. These results could be indicative, over a decade after the implementation of ACT therapy, of the return of chloroquine-sensitive but artemether-lumefantrine resistant falciparum genotypes in Benin. There was no evidence of HRP2 and HRP3 deletions. Data from the present study support the need for routine monitoring of molecular markers of antimalarial drug resistance as part of surveillance activities aimed to make informed treatment policy decisions at the national level.

Prevalence of parvovirus B19 antibodies in pregnant women in northern Benin.

OBJECTIVES: Parvovirus B19 (B19V) infection in pregnancy is generally asymptomatic, but in about 3% it can cause complications, including miscarriage, severe foetal anaemia and foetal hydrops. The seroprevalence in pregnancy ranges from 20% to 82% in Africa, but there are no data for Benin. We therefore retrospectively assessed the seroprevalence of B19V in pregnant women attending the Saint Jean de Dieu Hospital in Tanguiéta, a rural district of Atacora, in northern Benin. METHODS: We searched for anti-B19V immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in 227 sequential sera from as many women (mean age 26.3 years, range: 16-41) of whom 30 were in the first trimester, 66 in the second and 131 in the third. Samples that tested positive for IgM were analysed with an immunoblot test and the viral genome (DNA-B19V) was searched for using a polymerase chain reaction. RESULTS: Of the 227 women, 153 (67.4%) were positive for IgG anti-B19V, 7 (3.1%) for IgM and 73 (32.2%) were non-immune. Six IgM-positive women were also IgG positive. The difference in IgG seroprevalence between trimesters or ages was not statistically significant. Of the seven IgM-positive samples, three were confirmed positive by immunoblot (of which two were DNA-B19V positive), three were indeterminate (DNA-B19V negative) and one was negative (DNA-B19V negative). Of the three women with confirmed positive IgM, two were in the third trimester and one in the second trimester of pregnancy. CONCLUSIONS: The seroprevalence of anti-B19V IgG among pregnant women in Benin is high and in line with those reported in some African countries. IgM seroprevalence is also similar to that described in some African countries in non-epidemic periods. The low viral load observed depicts non-acute infections, but it is difficult to establish the precise time of the infection, especially for women tested in the second or third trimester of pregnancy, when the observed viremia could be a sign of an acute infection that occurred in the previous trimester. Consequently, clinical follow-up and further investigations to highlight possible foetal consequences are indicated.

Epidemiology of hepatitis E virus infection during pregnancy in Benin.

OBJECTIVES: Hepatitis E virus (HEV) is the cause of enterically transmitted non-A, non-C hepatitis (an infection that is particularly severe during pregnancy) in tropical and subtropical countries. As there are no published data concerning the prevalence of HEV antibodies in Benin, their presence was investigated in pregnant women undergoing routine HIV screening in a rural area in northern Benin and in pregnant women with acute non-A, non-C hepatitis. METHODS: A total of 278 serum samples were collected from asymptomatic pregnant women in 2011 were tested for HEV and hepatitis A virus (HAV) antibodies, and the HEV IgM-positive samples were further tested for HEV-RNA. A further seven samples of pregnant women with acute non-A, non-C hepatitis collected during episodes of acute hepatitis in 2005 were also analysed. RESULTS: Of the 278 samples collected in 2011, 16.19% were positive for HEV IgG and 1.44% for HEV IgM (none positive for HEV-RNA), and 99.64% were positive for total HAV antibodies (none positive for HAV IgM). Six of the seven samples collected in 2005 were positive for HEV IgG and IgM, and two were also positive for HEV-RNA. CONCLUSIONS: The circulation of HEV infection is significant among pregnant women in Benin, in whom the consequences may be fatal.

Prevalence of HBV, HDV, HCV, and HIV infection during pregnancy in northern Benin.

Pregnant women are not screened for HBsAg and anti-HCV antibodies in many African countries. As there are few data concerning the prevalence of HBV, HDV, and HCV serological markers in Benin, the aim of this study was to evaluate their 2011 prevalence in pregnant women undergoing HIV screening in a rural area of north Benin, and compare the data with those reported for the same area in 1986. The sera of 283 women were examined for HBsAg, anti-HBs, anti-HBc, anti-HCV, and anti-HIV 1/2 antibodies. In the case of HBsAg positivity, a search was made for the HBeAg, anti-HDV, and HBV genotypes; in the case of anti-HCV positivity, a search was made for the HCV genotypes. HBsAg, anti-HBs, anti-HBc, anti-HCV, and anti-HIV 1/2 were positive in respectively 44 (15.5%), 82 (29.0%), 234 (82.7%), 21 (7.4%), and nine samples (3.2%). Of the HBsAg-positive samples, five (11.4%) were positive for HBeAg, five (11.4%) for anti-HDV, and 19 for HBV genotype E. Of the anti-HCV-positive samples, five were positive for genotype 2a/2c and one for genotype 1a. The prevalence of anti-HBc alone (HBsAg and anti-HBs negative) was very high (41.3%). In comparison with the 1986 data, the prevalence of HBsAg and anti-HBc remained unchanged, that of HBeAg and anti-HDV had decreased, and that of anti-HIV 1/2 had increased. As these data confirm that HBV and HCV are highly endemic in the study area, it may be appropriate to introduce HBsAg and anti-HCV screening for pregnant women. J. Med. Virol. 86:1281-1287, 2014. © 2014 Wiley Periodicals, Inc.

Antenatal screening for Toxoplasma gondii, Cytomegalovirus, rubella and Treponema pallidum infections in northern Benin.

OBJECTIVES: Toxoplasma gondii, cytomegalovirus (HCMV) and rubella virus infections are among the most serious of those contracted during pregnancy in terms of foetal consequences. Toxoplasma, HCMV and rubella antibody screening is unusual in Africa, and there are few published data. The aim of this study was to evaluate the prevalence of these markers among pregnant women in northern Benin on the occasion of routine syphilis screening. METHODS: Toxoplasma, HCMV and rubella IgG and IgM antibodies were determined in the serum of 283 women attending Saint Jean de Dieu de Tanguiéta hospital, using an enzyme immunoassay, and IgM were confirmed using an enzyme-linked fluorescent assay (ELFA). In the case of IgM positivity, the avidity of anti-HCMV and anti-Toxoplasma IgG was measured. Total anti-Treponema pallidum antibodies were determined using an enzyme immunoassay and confirmed by immunoblotting. In the case of positivity, the Venereal Disease Research Laboratory (VDRL) test was used. RESULTS: The prevalence of anti-Toxoplasma, anti-HCMV, anti-rubella IgG and total anti-Treponema antibodies was, respectively, 30.0%, 100%, 94% and 2.5%. The VDRL test was positive in 62.5% of the anti-Treponema-positive samples. The prevalence of anti-Toxoplasma, anti-HCMV and anti-rubella IgM was, respectively, 0.4%, 1.4% and 0%. There were no statistically significant differences in terms of age class or trimester of pregnancy. Anti-Toxoplasma and anti-HCMV IgG avidity was always high. CONCLUSIONS: The prevalence of HCMV and rubella antibodies is high in northern Benin, whereas that of Toxoplasma antibodies is lower. As nearly two-thirds of the pregnant women were anti-Toxoplasma seronegative, antibody screening should be introduced.

Revision of the positive predictive value of IgM anti-Toxoplasma antibodies as an index of recent infection.

The severity of congenital Toxoplasma gondii infection underlines the need for a precise diagnosis of acute infection during pregnancy. The search for specific IgM has been widely used for this purpose, but their possible early disappearance or persistence over time limits their meaning. In order to estimate the positive predictive value of anti-Toxoplasma IgM testing, we made an epidemiological analysis of the presence of anti-Toxoplasma IgG and IgM using ELISA in 4786 subjects attending the Hospital of Legnano in 2004-2005: 1360 seen for a clinical check-up and 3426 pregnant women for serological screening. In relation to IgG avidity, the positive predictive value of IgM was 45.98% (95% CI: 35.51-56.45) as a whole: this increased to 83.87% (95% CI: 70.92-96.82) in the patients with a highly positive test for IgM, but decreased to 9.52% (95% CI: 0.00-22.07) in pregnant women with a weakly positive test for IgM. Our results indicate that a highly positive IgM value in patients can be a good index of recent infection, but its poor predictive value in pregnant women underlines the need for additional tests with a follow-up if necessary.