Rate of treatment success and associated factors in the program for drug-susceptible tuberculosis in the Forest Region, Republic of Guinea, 2010-2017: A real-world retrospective observational cohort study

OBJECTIVES

To analyze the treatment success rate (TSR = sum of cured or treatment completed) in the tuberculosis (TB) program for drug-susceptible TB (DS-TB) at the "Centre Hospitalier Régional Spécialisé" in Macenta, Forest Region, Republic of Guinea.

METHODS

This cohort study included patients who started treatment for DS-TB between 2010 and 2017. Data collection was part of the documentation for the national TB program. Descriptive analysis was applied to determine the TSR in various patient groups. Further, logistic regression was performed to determine factors influencing the TSR in new and relapsed cases versus all other previously treated cases. A subgroup analysis for only microbiologically confirmed pulmonary TB was added.

RESULTS

The study included 3969 patients. The TSR increased from 68.3% in 2010 to 80.8% in 2017 (p < 0.001). Mortality (11.2%) mainly occurred in early treatment months, while loss to follow-up (5.9%) increased towards later treatment months. Risk factors for low TSR were advanced age, positive HIV status, long travel distances (>100 km) to the clinic, and late treatment refill.

CONCLUSION

The TSR in the Forest Region of Guinea remained below the WHO goal of 90%. Reaching this target remains a challenge in rural areas with high early mortality and increased risk of loss to follow-up.

Characterization and analytical validation of a new antigenic rapid diagnostic test for Ebola virus disease detection

Hemorrhagic fever outbreaks are difficult to diagnose and control in part because of a lack of low-cost and easily accessible diagnostic structures in countries where etiologic agents are present. Furthermore, initial clinical symptoms are common and shared with other endemic diseases such as malaria or typhoid fever. Current molecular diagnostic methods such as polymerase chain reaction require trained personnel and laboratory infrastructure, hindering diagnostics at the point of need, particularly in outbreak settings. Therefore, rapid diagnostic tests such as lateral flow can be broadly deployed and are typically well-suited to rapidly diagnose hemorrhagic fever viruses, such as Ebola virus. Early detection and control of Ebola outbreaks require simple, easy-to-use assays that can detect very low amount of virus in blood. Here, we developed and characterized an immunoassay test based on immunochromatography coupled to silver amplification technology to detect the secreted glycoprotein of EBOV. The glycoprotein is among the first viral proteins to be detected in blood. This strategy aims at identifying infected patients early following onset of symptoms by detecting low amount of sGP protein in blood samples. The limit of detection achieved by this sGP-targeted kit is 2.2 x 10⁴ genome copies/ml in plasma as assayed in a monkey analytical cohort. Clinical performance evaluation showed a specificity of 100% and a sensitivity of 85.7% when evaluated with plasma samples from healthy controls and patients infected with Zaire Ebola virus from Macenta, Guinea. This rapid and accurate diagnostic test could therefore be used in endemic countries for early detection of infected individuals in point of care settings. Moreover, it could also support efficient clinical triage in hospitals or clinical centers and thus reducing transmission rates to prevent and better manage future severe outbreaks.

Ebola virus disease is a severe disease caused by Ebola virus, a member of the filovirus family, which occurs in humans and other primates. Ebola is believed to be zoonotic, however the natural reservoir is unknown. Overlapping symptoms with other endemic diseases, such as malaria and cholera, make accurate diagnostic challenging. Outbreaks of Ebola have been widespread as the consequence of the absence of available rapid, sensitive, specific, robust, and affordable licensed diagnostic test in remote areas, where outbreaks usually start. Here we have established and validated a rapid diagnostic test, which is fast, sensitive, specific, efficient, affordable, and user-friendly. Its analytical characteristics make it suitable for clinical management during Ebola virus outbreaks in remote areas. Of interest, this rapid diagnostic test detects the presence of an early viral antigen, the secreted glycoprotein, found in blood of patients shortly after infection, suggesting that it could be used to identify infected patients shortly after onset of symptoms.