First molecular-based anti-TB drug resistance survey in Eritrea.

BACKGROUND: In the absence of reliable data on drug-resistant TB in Eritrea, a national survey was conducted in 2018 using molecular-based methods, bypassing the need for culture.METHODS: A cross-sectional study was conducted in all 77 TB microscopy centres in the country. All 629 newly registered sputum smear-positive pulmonary TB patients were enrolled over 12 months. Sputum samples were tested using the Xpert® MTB/RIF assay and targeted next-generation sequencing (Deeplex Myc-TB) to identify resistance and explore the phylogenetics of Mycobacterium tuberculosis complex strains.RESULTS: Drug resistance profiles were obtained for 555 patients (502 new, 53 previously treated). The prevalence of rifampicin-resistant TB (RR-TB) was respectively 2.0% and 7.6% among new and previously treated cases. All RR-TB isolates that were susceptible to isoniazid displayed a phylogenetic marker conferring capreomycin resistance, confirming circulation of a previously described resistant TB sub-lineage in the Horn of Africa. Only one case of fluoroquinolone resistance was detected.CONCLUSION: The prevalence of rifampicin resistance among TB patients is encouragingly low. The scarcity of fluoroquinolone resistance bodes well for the success of the recommended all-oral treatment regimen. Surveillance based on molecular approaches enables a reliable estimation of the burden of resistance and can be used to guide appropriate treatment and care.

Ethiopia's transforming wheat landscape: tracking variety use through DNA fingerprinting.

Ethiopia is the largest wheat producer in sub-Saharan Africa yet remains a net importer. Increasing domestic wheat production is a national priority. Improved varieties provide an important pathway to enhancing productivity and stability of production. Reliably tracking varietal use and dynamics is a challenge, and the value of conventional recall surveys is increasingly questioned. We report the first nationally representative, large-scale wheat DNA fingerprinting study undertaken in Ethiopia. Plot level comparison of DNA fingerprinting with farmer recall from nearly 4000 plots in the 2016/17 season indicates that only 28% of farmers correctly named wheat varieties grown. The DNA study reveals that new, rust resistant bread wheat varieties are now widely adopted. Germplasm originating from CGIAR centres has made a significant contribution. Corresponding productivity gains and economic benefits have been substantial, indicating high returns to investments in wheat improvement. The study provides an accurate assessment of wheat varietal status and sets a benchmark for national policy-makers and donors. In recent decades, the Ethiopian wheat landscape has transformed from local tetraploid varieties to widespread adoption of high yielding, rust resistant bread wheat. We demonstrate that DNA fingerprinting can be applied at scale and is likely to transform future crop varietal adoption studies.

Maternal rubella-specific antibody prevalence in Ethiopian infants.

In countries with a high transmission rate of rubella the optimal age for universal rubella vaccination of infants is critically dependent upon the rate of loss of maternal antibodies. Few studies have investigated the decay characteristics of such antibodies. Mother:infant pairs were recruited at the Ethio-Swedish Children's Hospital, Addis Ababa, in 1994/95. Rubella antibody levels, determined by radial haemolysis, were available for analysis from 1542 infants aged 0-12 months, with 942 repeat measures, and from 846 mothers. Decay in seropositivity was well described by a delayed exponential function. The proportion seropositive at age 6, 9, or 12 months was 6-13%, 1-4%, or 0-1%, respectively, dependent upon assay cutoff level. Only infant age and mother's antibody level were important predictors of seropositivity. Results suggest that the success of vaccination at age 9 months or above would be little affected by residual maternal antibodies.

Timing of development of measles-specific immunoglobulin M and G after primary measles vaccination.

A standard method for diagnosing measles is to detect measles-specific immunoglobulin M (IgM) in the serum of infected persons. Interpreting a positive IgM result from a person with suspected measles can be difficult if the person has recently received a measles vaccine. We have previously demonstrated that measles-specific IgM may persist for at least 8 weeks after primary vaccination, but it is unknown how quickly IgM appears. This study determined the timing of the rise of measles-specific IgM and IgG after primary measles vaccination with Schwartz vaccine. Two hundred eighty 9-month-old children from Ethiopia presenting for routine measles vaccination were enrolled. Sera were collected before and either 1, 2, 3, or 4 weeks after vaccination and tested for measles-specific antibodies by an IgM capture enzyme immunoassay (EIA) and by an indirect IgG EIA. A total of 209 of the 224 children who returned for the second visit had prevaccination sera that were both IgM and IgG negative. The postvaccination IgM positivity rates for these 209 children were 2% at 1 week, 61% at 2 weeks, 79% at 3 weeks, and 60% at 4 weeks. The postvaccination IgG positivity rates were 0% at 1 week, 14% at 2 weeks, 81% at 3 weeks, and 85% at 4 weeks. We conclude that an IgM-positive result obtained by this antibody capture EIA is difficult to interpret if serum is collected between 8 days and 8 weeks after vaccination; in this situation, the diagnosis of measles should be based on an epidemiologic linkage to a confirmed case or on the detection of wild-type measles virus.

The effect of timing of sample collection on the detection of measles-specific IgM in serum and oral fluid samples after primary measles vaccination.

This study compares the timing of the rise and decline of measles-specific IgM in serum samples and in oral fluid samples. Two hundred and eighty 9-month-old infants presenting for routine measles vaccination in Addis Ababa, Ethiopia, were enrolled. Paired serum and oral fluid samples were collected before and 1, 2, 3 or 4 weeks after measles vaccination. Samples were tested by using a modified antibody-capture enzyme immunoassay. For the 321 IgM-negative pre- and post-vaccination serum samples, 317 (99 %) of their corresponding oral fluid samples were IgM-negative. Among the 130 IgM-positive serum samples, 75% of their paired oral fluid samples were IgM-positive, with the percentage rising to 87% after oral fluid samples collected > or =3.5 weeks after vaccination were excluded. Among the post-vaccination serum samples, the percent IgM-positive peaked in week 3 and declined to 79% in week 4. For post-vaccination oral fluid samples, the percent IgM-positive peaked in weeks 2 and 3, and then declined to 43% in week 4. This modified antibody-capture enzyme immunoassay appears to detect vaccine-induced measles-specific IgM in the first 3 weeks after vaccination.

Comparative detection of measles-specific IgM in oral fluid and serum from children by an antibody-capture IgM EIA.

In vaccinated populations, the diagnosis of measles often requires laboratory confirmation. Serum tested by EIAs has proven sensitive and specific for diagnosing measles. For comparison of detection of measles-specific IgM in oral fluid and serum samples by an antibody-capture EIA, 163 Ethiopian infants who presented for routine measles vaccination were studied. Paired serum and oral fluid samples were collected before and 2 weeks after vaccination; 269 paired samples were adequate for analyses. Of the 104 serum samples that were IgM-positive, 95 (91%) of the paired oral fluid samples were IgM-positive. Of the 165 serum samples that were IgM-negative, 156 (95%) of the paired oral fluid samples were IgM-negative. The Pearson partial correlation coefficient for optical density readings from postvaccination oral fluid compared with serum was 0.81. Oral fluid appears to be an acceptable alternative to serum for measuring measles-specific IgM antibodies by an antibody-capture EIA.

Relapsing fever in children--demographic, social and clinical features.

Louse-borne relapsing fever (LBRF) is an acute febrile illness endemic Ethiopia. To date reports of childhood LBRF are few. The demographic, social and clinical features of eighty children with LBRF admitted to Ethio-Swedish Children's Hospital, Addis Abeba between 1989 and 1991 is presented. The mean age of patients was 8.8 years (range 4 months to 15 years). The male to female ratio was 1.2:1. Seventy-seven (97%) patients came from Addis Abeba. They came from poor families living in overcrowded homes. Fever, headache, right upper quadrant pain, chills and rigors were common symptoms. Fever and hepatosplenomegaly were common signs. Three drug regimens were used in the treatment of patients. A combination of penicillin and tetracycline, chloramphenicol alone and erythromycin alone, all given for 3 days. There was only one death. The literature on LBRF in adults is reviewed and the results are compared (1).

Clinical and epidemiological features of HIV-1 seropositive hospitalized Ethiopian children.

Eleven children were identified as being seropositive for HIV-1 at the Ethio-Swedish Children's Hospital, Addis Abeba, Ethiopia between January 1988 and September 1989. The diagnosis was confirmed by both ELISA and Western blot methods performed at the National Research Institute of Health, Special Laboratory for AIDS. The mean age was 2 years and 5 months, with a range of 1 week to 10 years. There were 7 boys and 4 girls. The most common admitting diagnoses were pneumonia (5), gastroenteritis (5), marasmus (5), disseminated tuberculosis (4), and abandonment (3). One patient had extensive facial molluscum contagiosum. Symptoms at admission or during hospitalization included diarrhoea (9), failure to thrive (8), fever (7), and cough (7). Physical findings included hepatosplenomegaly (5), lymphadenopathy (3), and oral candidiasis (2). No patient with an opportunistic infection or radiographic evidence of lymphocytic interstitial pneumonitis (LIP) was identified. Five patients were classified as marasmic and 4 as underweight. Evidence suggestive of encephalopathy (developmental delay and/or microcephaly) was present in 5 patients. The VDRL was non-reactive in the 5 patients in whom it was tested. Nine children were presumed to have acquired the infection by perinatal transmission, though the passive transfer of maternal antibodies or postnatally acquired infection could not be excluded. One child was thought to have acquired the infection by blood transfusion. Three children died during their hospital stay. Paediatric HIV infection exists in Ethiopia; however, these children do not present with characteristic opportunistic infections but with signs and symptoms reflecting the most common paediatric problems seen in the country. Prevention of HIV infection in children entails the prevention of infection in women of childbearing age, counselling of infected women, and effective screening of blood products.