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Dive into the research topics where Mohammed A. Yassin is active.

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Featured researches published by Mohammed A. Yassin.


Tropical Medicine & International Health | 2005

Rural poverty and delayed presentation to tuberculosis services in Ethiopia

Alexis Cambanis; Mohammed A. Yassin; Andrew Ramsay; S. Bertel Squire; Isabel Arbide; Luis E. Cuevas

To measure time to initial presentation and assess factors influencing the decision to seek medical attention, we interviewed 243 patients undergoing sputum examination for the diagnosis of tuberculosis (TB) at a rural health centre near Awassa, Ethiopia. A structured questionnaire was used. Median (mean + SD) patient delay was 4.3 (9.8 + 12.4) weeks. Delays over 4 weeks were significantly associated with rural residence, transport time over 2 h, overnight travel, transport cost exceeding US


Journal of Clinical Microbiology | 2002

Identification of the Causative Organism of Tuberculous Lymphadenitis in Ethiopia by PCR

Dawit Kidane; Joseph Olobo; Abebe Habte; Yohannes Negesse; Abraham Aseffa; Getahun Abate; Mohammed A. Yassin; Kiflu Bereda; Morten Harboe

1.40, having sold personal assets prior to the visit, and use of traditional medicine. The majority of patients cited economic or logistical barriers to health care when asked directly about causes of delay. Case‐finding strategies for TB must be sensitive to patient delay and health systems must become more accessible in rural areas.


PLOS ONE | 2013

Innovative Community-Based Approaches Doubled Tuberculosis Case Notification and Improve Treatment Outcome in Southern Ethiopia

Mohammed A. Yassin; Daniel Gemechu Datiko; Olivia Tulloch; Paulos Markos; Melkamsew Aschalew; Estifanos Biru Shargie; Mesay Hailu Dangisso; Ryuichi Komatsu; Suvanand Sahu; Lucie Blok; Luis E. Cuevas; Sally Theobald

ABSTRACT Tuberculous lymphadenitis (TBLN) is a common form of extrapulmonary tuberculosis with multiple differential diagnoses. Demonstration of the etiologic agent by smear microscopy or culture of fine needle aspirate (FNA) specimens is often unsuccessful. FNA specimens from 40 patients presenting at a rural health center in South Ethiopia and diagnosed as positive for TBLN on the basis of clinical and cytological criteria were analyzed for mycobacterial DNA by PCR. Thirty (75%) had cervical lymphadenitis and 11 (27.5%) were seropositive for human immunodeficiency virus (HIV). Three primer sets were initially used to identify the causative agent at the genus (antigen 85 complex), complex (IS6110 insertion sequence), and species (pncA gene and allelic variation) levels. Among the forty TBLN cases, 35 (87.5%) were positive by PCR at the genus and complex levels. Based on PCR for detection of allelic variation at position 169, 24 (68.6%) of the 35 were positive for Mycobacterium tuberculosis and 6 (17.1%) were positive for M. bovis. These six were positive in additional PCR assays using the JB21-JB22 primer set, which is highly specific for M. bovis. Five (14.1%) showed amplification for both M. tuberculosis and M. bovis with the allele-specific primer set. Cooccurrence of pyrazinamide (PZA)-sensitive and -resistant M. tuberculosis in those five cases was indicated, since all were negative in assays with the JB21-JB22 primer set. This feature was seen in 3 of 11 HIV-positive and 2 of 29 HIV-negative individuals (P < 0.001). Conclusion: among 35 PCR-positive cases of TBLN from southern Ethiopia, 29 (82.9%) were caused by M. tuberculosis and six (17.1%) were caused by M. bovis.


Scandinavian Journal of Infectious Diseases | 2004

HIV and tuberculosis coinfection in the southern region of ethiopia: A prospective epidemiological study

Mohammed A. Yassin; Luelseged Takele; Sahlemariam Gebresenbet; Emebet Girma; Meskele Lera; Ersido Lendebo; Luis E. Cuevas

Background TB Control Programmes rely on passive case-finding to detect cases. TB notification remains low in Ethiopia despite major expansion of health services. Poor rural communities face many barriers to service access. Methods and Findings A community-based intervention package was implemented in Sidama zone, Ethiopia. The package included advocacy, training, engaging stakeholders and communities and active case-finding by female Health Extension Workers (HEWs) at village level. HEWs conducted house-to-house visits, identified individuals with a cough for two or more weeks, with or without other symptoms, collected sputum, prepared smears and supervised treatment. Supervisors transported smears for microscopy, started treatment, screened contacts and initiated Isoniazid preventive therapy (IPT) for children. Outcomes were compared with the pre-implementation period and a control zone. Qualitative research was conducted to understand community and provider perceptions and experiences. HEWs screened 49,857 symptomatic individuals (60% women) from October 2010 to December 2011. 2,262 (4·5%) had smear-positive TB (53% women). Case notification increased from 64 to 127/100,000 population/year resulting in 5,090 PTB+ and 7,071 cases of all forms of TB. Of 8,005 contacts visited, 1,949 were symptomatic, 1,290 symptomatic were tested and 69 diagnosed with TB. 1,080 children received IPT. Treatment success for smear-positive TB increased from 77% to 93% and treatment default decreased from 11% to 3%. Service users and providers found the intervention package highly acceptable. Conclusions Community-based interventions made TB diagnostic and treatment services more accessible to the poor, women, elderly and children, doubling the notification rate and improving treatment outcome. This approach could improve TB diagnosis and treatment in other high burden settings.


PLOS Medicine | 2011

A Multi-Country Non-Inferiority Cluster Randomized Trial of Frontloaded Smear Microscopy for the Diagnosis of Pulmonary Tuberculosis

Luis E. Cuevas; Mohammed A. Yassin; Najla Al-Sonboli; Lovett Lawson; Isabel Arbide; Nasher Al-Aghbari; Jeevan B. Sherchand; Amin Al-Absi; Emmanuel Nnamdi Emenyonu; Yared Merid; Mosis Ifenyi Okobi; Juliana Olubunmi Onuoha; Melkamsew Aschalew; Abraham Aseffa; Greg Harper; Rachel Anderson de Cuevas; Kristin Kremer; Dick van Soolingen; Carl-Michael Nathanson; Jean Joly; Brian Faragher; Stephen Bertel Squire; Andrew Ramsay

HIV has played a key role in TB, modifying its incidence and clinical presentation. This study describes the prevalence of HIV among TB patients attending health facilities in the southern region of Ethiopia. The HIV prevalence was 18% for female and 21% for male TB patients. 15% and 30%, respectively, of the rural and urban patients with TB were HIV positive (p<0.05). 19% (51/261) smear-positive PTB, 26% (36/137) smear-negative PTB and 11% (10/94) of the extrapulmonary TB patients were HIV positive. The proportion of patients with extra-PTB varied from 11% to 38% across the centres and was highest in the zones with the lowest HIV prevalence. In the light of limited diagnostic facilities, clinicians often make a clinical diagnosis of TB without laboratory confirmation. The increase in the number of TB cases could be due to HIV. However, the number of health facilities offering TB treatment in the area also increased (from 53 to 236) during the same period and the increase in TB is likely to be the result of a combination of factors, including improved detection and HIV. It is important to consider this multi-factorial phenomenon when interpreting the increase of TB in a geographical area.


PLOS Medicine | 2011

LED Fluorescence Microscopy for the Diagnosis of Pulmonary Tuberculosis: A Multi-Country Cross-Sectional Evaluation

Luis E. Cuevas; Najla Al-Sonboli; Lovett Lawson; Mohammed A. Yassin; Isabel Arbide; Nasher Al-Aghbari; Jeevan B. Sherchand; Amin Al-Absi; Emmanuel Nnamdi Emenyonu; Yared Merid; Mosis Ifenyi Okobi; Juliana Olubunmi Onuoha; Melkamsew Aschalew; Abraham Aseffa; Greg Harper; Rachel Anderson de Cuevas; Sally Theobald; Carl-Michael Nathanson; Jean Joly; Brian Faragher; Stephen Bertel Squire; Andrew Ramsay

Luis Cuevas and colleagues report findings from a multicenter diagnostic clinical trial in tuberculosis, showing that the sensitivity and specificity of a “front-loaded” diagnostic scheme is not inferior to that of a standard diagnostic scheme.


BMC Public Health | 2008

The rate of TB-HIV co-infection depends on the prevalence of HIV infection in a community

Daniel Gemechu Datiko; Mohammed A. Yassin; Luelseged T. Chekol; Lopisso E. Kabeto; Bernt Lindtjørn

This study, nested within a clinical trial, by Luis Cuevas and colleagues finds that LED-FM microscopy has higher sensitivity but lower specificity than Zn microscopy for detecting tuberculosis in sputum samples.


Tropical Medicine & International Health | 2007

Duration and associated factors of patient delay during tuberculosis screening in rural Cameroon

Alexis Cambanis; Andrew Ramsay; Mohammed A. Yassin; Luis E. Cuevas

BackgroundA complex interaction exists between tuberculosis (TB) and human immunodeficiency virus (HIV) infection at an individual and community level. Limited knowledge about the rate of HIV infection in TB patients and the general population compromises the planning, resource allocation and prevention and control activities. The aim of this study was to determine the rate of HIV infection in TB patients and its correlation with the rate HIV infection in pregnant women attending antenatal care (ANC) in Southern Ethiopia.MethodsAll TB patients and pregnant women attending health institutions for TB diagnosis and treatment and ANC were consecutively enrolled in 2004 – 2005. TB diagnosis, treatment and HIV testing were done according to the national guidelines. Blood samples were collected for anonymous HIV testing. We used univariate and multivariate logistic regression analysis to determine the risk factors for HIV infection and linear regression analysis to determine the correlation between HIV infection in TB patients and pregnant women.ResultsOf the 1308 TB patients enrolled, 226 (18%) (95%CI: 15.8 – 20.0) were HIV positive. The rate of HIV infection was higher in TB patients from urban 25% (73/298) than rural areas 16% (149/945) [AOR = 1.78, 95%CI: 1.27–2.48]. Of the 4199 pregnant women attending ANC, 155 (3.8%) [95%CI: 3.2–4.4] were HIV positive. The rate of HIV infection was higher in pregnant women from urban (7.5%) (80/1066) than rural areas (2.5%) (75/3025) [OR = 3.19, 95% CI: 2.31–4.41]. In the study participants attending the same health institutions, the rate of HIV infection in pregnant women correlated with the rate of HIV infection in TB patients (R2 = 0.732).ConclusionThe rate of HIV infection in TB patients and pregnant women was higher in study participants from urban areas. The rate of HIV infection in TB patients was associated with the prevalence of HIV infection in pregnant women attending ANC.


Tropical Medicine & International Health | 2003

Comparison of screening methods for anaemia in pregnant women in Awassa, Ethiopia

S. Gies; Bernard J. Brabin; Mohammed A. Yassin; Luis E. Cuevas

Objectives  (i) To determine patient delay – the time from the onset of symptoms to presentation at a health facility – and its causes in patients undergoing sputum smear examination in Cameroon; and (ii) to compare the results with those of a previous study in Ethiopia.


Pediatric Infectious Disease Journal | 2008

Interferon gamma, interferon-gamma-induced-protein 10, and tuberculin responses of children at high risk of tuberculosis infection.

Roberta Petrucci; Nabil Abu Amer; Ricardo Queiroz Gurgel; Jeevan B. Sherchand; Luiza Doria; Chamala Lama; Pernille Ravn; Morten Ruhwald; Mohammed A. Yassin; Gregory Harper; Luis E. Cuevas

Screening for anaemia in pregnancy is essential for implementing and monitoring effective antenatal programmes. We compared the diagnostic accuracy of invasive and non‐invasive screening methods in a cross‐sectional survey of 403 pregnant women attending an urban health centre in Awassa, southern Ethiopia. Overall anaemia prevalence [haemoglobin (Hb): <11 g/dl] was 15.1% (95% CI: 12.1–19.9), mild anaemia (Hb: 10–10.9 g/dl) 10.4%, moderate anaemia (Hb: 7–9.9 g/dl) 4.2% and severe anaemia (Hb < 7 g/dl) 0.3%. Sensitivity, specificity and predictive values of conjunctival pallor and the WHO Hb colour scale were calculated for Hb cut‐off points <11, <10 and <9 g/dl. All methods in combination with the symptoms and complaints reported by the mothers were entered into a predictive scoring system. None of the methods tested or models predicted anaemia with suitable accuracy in this population. The diagnosis of anaemia based on clinical signs and symptoms remains unreliable despite attempts to develop predictive models.

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Luis E. Cuevas

Liverpool School of Tropical Medicine

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Daniel Gemechu Datiko

Liverpool School of Tropical Medicine

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Sally Theobald

Liverpool School of Tropical Medicine

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Stephen Bertel Squire

Liverpool School of Tropical Medicine

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Nasher Al-Aghbari

National Tuberculosis Institute

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Rachel Anderson de Cuevas

Liverpool School of Tropical Medicine

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