Silent epidemic of silicotuberculosis in India and emergence of multidrug-resistant tuberculosis?

OBJECTIVES: India's projected silica-dust-exposed workers will be 52 million at the end of 2025. The elimination of tuberculosis (TB) is also targeted in India by 2025. Scientists in India have already pointed out that unless silicosis is controlled, the said elimination will be difficult to achieve. METHODS AND RESULTS: This study provides evidence of an increasing incidence of tuberculosis (TB) including multidrug-resistant TB (MDR-TB) with mortality owing to treatment failure among the silica dust-exposed workers compared to their unexposed counterpart. It was also observed that TB as well as MDR-TB were directly proportional to the dose and/or duration of silica dust exposure (progression of silica-dust induced lung damage). This means the occurrence of both TB and MDR-TB is lowest in the unexposed group, moderate in the radiologically negative but silica dust-exposed group (subradiological silicosis owing to moderate exposure), and highest in the radiologically confirmed silicotic workers (maximally exposed group). Because India has a huge burden of silicosis cases, the said cases are vulnerable to pulmonary TB, including MDR-TB. The study indicates there will be an emergence of MDR-TB among the silica dust-exposed workers unless appropriate intervention measures are initiated with immediate effect. Failure to do so, it will probably lead to a silent epidemic of silicotuberculosis in India shortly. CONCLUSIONS: It is important to have tools to detect silicosis cases quickly and at an early stage to identify a vulnerable population and adopt an effective intervention measure.

A cluster onset of acute and accelerated silicosis cases in workers of ramming mass industries in Jharkhand, Eastern India.

Introduction and Methodology: A cross-sectional study was conducted among workers of ramming mass industries in the East Singhbhum district of Jharkhand, eastern India. Workers had occupational exposure to respirable crystalline silica dust of varied duration between 1 and 6 years. A total of 122 subjects participated in it. Relevant epidemiological information was collected from them. All were x-rayed using 300 mA radiation for the detection of the presence of silicotic opacities if any as described by the International Labour Organisation (ILO) for the detection of silicosis. Results: The study revealed that 61.4% (n = 75) of subjects had silicosis. Of them, 19 had acute silicosis (having a duration of silica dust exposure of 2 years or lesser) and 56 had accelerated silicosis (a duration of occupational exposure of > 2 to 6 years). The offending agent was clouds of respirable crystalline silica dust from the ramming mass industries. Epidemiological Interpretation: To the best of our knowledge, this is the first report of an outbreak of acute and accelerated silicosis cases because of occupational inhalational exposure to ramming mass in India with a sizable portion of female workers with silicosis. Regional as well as national authorities need to take appropriate interventional measures in a programmatic mode as soon as possible. Conclusion: An in-depth investigation on the existence and magnitude of the problem of silico-tuberculosis is needed to be performed in them as silicosis increases the vulnerability of pulmonary tuberculosis among the affected workers.

Elimination of tuberculosis requires prior control of silicosis including sub-radiological silicosis.

India is committed to the elimination of tuberculosis by 2025. But its achievement appears to be difficult as India has a huge burden of silicosis as well as sub-radiological silicosis, which was never given its required attention. Silicotic subjects are highly vulnerable to pulmonary tuberculosis due to the progressive decline of lung immunity. A study among vulnerable glass factory workers in Firozabad, Uttar Pradesh, revealed that silicotic workers were 7.5 times more at risk of pulmonary tuberculosis compared to non-silicotic subjects. Since India has a huge burden of silicosis and sub-radiological silicosis, the elimination of tuberculosis needs prior attention on silicosis. This article may be viewed as an eye-opener for understanding the necessity of dual control of both silicosis as well as tuberculosis by integrating both together.

Intra-Familial Transmission Patterns of COVID-19 Infection among the Rural Residents of Ahmedabad, Gujarat, during an Epidemic of SARS-CoV-2 in India.

We are yet to completely understand the transmission dynamics of coronavirus disease 2019 (COVID-19), a highly infectious disease, and research exploring the same is currently lacking. Hence, a community-based cross-sectional study was conducted to assess the intra-familial transmission pattern of COVID-19 among the rural residents of Ahmedabad, Gujarat, in relation to possible determinants, with a special focus on the viral load as an important factor. This cross-sectional study included visiting 195 families. We interviewed families with at least one case of COVID-19 infection. We recorded information about sociodemographic profiles and secondary transmission of cases. Out of the 195 families, 114 confirmed having at least one infected case within the family. Approximately 38.6% (44/114) of the index cases were asymptomatic, which was much higher than the low viral load index cases. Index cases with high, moderate, and low viral loads had transmitted the infection with an average of 3.3, 1.5, 0.4 secondary cases per index case, respectively. Approximately one-third of the COVID-19 cases were asymptomatic, and the affected individuals were capable of transmitting the disease within families. Moreover, index cases with a higher viral load had a higher transmission potential to generate more secondary cases, as compared to those with a low viral load.

Secondary prevention of silicosis and silico-tuberculosis by periodic screening of silica dust exposed workers using serum club cell protein 16 as a proxy marker.

BACKGROUND AND OBJECTIVES: Silicosis is a neglected and widely prevalent occupational disease in India and several other countries such as China, South Africa, Brazil, etc. It is an irreversible, incurable, and progressive disease with high morbidity and mortality, which is mostly caused by occupational exposure to silica dusts. Silicosis is usually detected at an advanced stage, when effective intervention is not possible. But early detection appears to be a cost-effective way to control it. There is a need for some suitable biomarker, which could detect silicosis at an early stage for further necessary intervention. This study aimed to estimate the lung damage in silicotic subjects and its relationship with serum CC16 as a proxy marker. The ultimate objective was to explore whether CC16 could be used as a screening tool for early detection of silicosis. METHODOLOGY: Radiographs of 117 workers having radiological evidences of silicosis were evaluated in accordance with International Labour Organisation (ILO) Classification of chest radiographs and were categorized as mild, moderate, and severe lung damage using a lung damage scoring system, made for the purpose of this study. The concentration of CC16 in serum was determined by enzyme-linked immunosorbent assay. RESULT: It was observed that serum CC16 values were significantly decreased in relation to increasing lung damage. The mean ± standard deviation (SD) serum CC16 value in mild lung damage group was 8.4 ± 0.87 ng/mL as compared to 4.0 ± 2.10 ng/mL in moderate and 0.7 ± 0.21 ng/mL in high lung damage groups. On the other hand, CC16 value of control (healthy) population was found to be 16.3 ± 3.8 ng/mL. CONCLUSION: Result of the study concluded that serum CC16 might be used as a periodic screening tool for early detection of silicosis and for it's secondary prevention. It may be viewed as a new approach toward control of silicosis, and an appropriate policy may be adopted.

Initial Viral Load of a COVID-19-Infected Case Indicated by its Cycle Threshold Value of Polymerase Chain Reaction Could be used as a Predictor of its Transmissibility - An Experience from Gujarat, India.

BACKGROUND: Transmission dynamics of the infectious disease Corona Virus Disease - 19 (COVID-19) is yet to be understood fully. The study aimed at exploring whether quantitative viral load of COVID-19-infected case indicated by cycle threshold (Ct) value of real-time reverse transcription polymerase chain reaction could predict about transmission pattern in the community. MATERIALS AND METHODS: An observational study was conducted involving 1976 individuals, suspected to be suffering from COVID-19 and contacts, of laboratory confirmed cases from selected districts of Gujarat, India. A total of 138 persons were detected to be positive. Weekly positivity showed an overall increasing trend during the studied weeks. It was observed that only 7% had high, 9% as moderate and rest, 84% had low viral load based on Ct values of real-time RT-PCR. RESULTS: Most secondary cases clustered around index cases with high viral load whereas fewer secondary cases clustered around index cases with low viral load. Each index high viral load case transmitted an average of 6.25 secondary cases whereas the same of low viral load transmitted an average of 0.8 case. CONCLUSION: If cases with higher viral load are selectively isolated on detection from the rest of the community along with contact tracing of all individuals, who came in contact with them during the previous 5 days, the quantum of transmission will reduce subsequently. Moreover, health-care workers often get infected while working, probably due to the fact that they often handle cases with higher viral load. The Ct value of all may be provided along with test report to safeguard everybody's health including health-care workers.

Club cell protein 16 as a biomarker for early detection of silicosis.

Background & objectives: Clinically silicosis is diagnosed by chest X-ray showing specific opacities along with history of silica dust exposure. Diagnosis is invariably made at an advanced or end stage when it is irreversible. Moreover, silicosis patients are susceptible to develop tuberculosis. Therefore, a suitable biomarker for early detection of silicosis is needed. This study evaluated the suitability of club cell protein (CC16) as a biomarker for early detection of silicosis. Methods: This pilot study included 121 individuals from X-ray-confirmed/advanced silicosis, moderate silica dust-exposed workers and healthy controls from western India. CC16 levels were quantified in serum samples through ELISA. Sensitivity and specificity of CC16 values at different cut-off points were calculated in both non-smokers and smokers. Results: Serum CC16 level was significantly (P <0.01) decreased in X-ray confirmed advanced silicosis patients (4.7±3.07 ng/ml) followed by moderately exposed workers (10.2±1.77 ng/ml) as compared to healthy non-exposed individuals (16.7±3.81 ng/ml). Tobacco smoking also caused a significant decrease of serum CC16 concentration in both healthy (10.2±1.12 ng/ml) and advanced silicosis workers (2.6±2.28 ng/ml) compared to non-smokers. Sensitivity and specificity of CC16 values were also found to be ≥83 per cent for screening all categories of individuals. Interpretation & conclusions: Because of high sensitivity and specificity, serum CC16 could be used as predictive biomarker for suspicion and early detection of silicosis, which would help in reducing/delaying premature deaths caused by silicosis. It would also control silicotuberculosis additionally.

COVID control strategy--is there any light at the end of the tunnel?

CONTEXT: India has been witnessing a huge surge of COVID-19 cases, with increasing number of new cases and deaths daily. There is yet no effective vaccine, drug or strategy to combat this disease. Various models of COVID-19 trend and management have been put forward by different researchers, yet no prediction has yet turned out to be close to the reality. AIMS: To find an effective public health strategy against COVID control. SETTINGS AND DESIGN: Ahmedabad district in Gujarat. METHODS AND MATERIAL: Ahmedabad Model for control of COVID-19 based on Ct threshold has been put forth which stresses upon the fact that higher viral load (super-spreaders) could be an important determinant in spreading infections in the community. RESULTS: The cycle threshold (Ct)-based segregation of laboratory-confirmed positive cases along with contact tracing of all of them of previous 5 days has been found to be effective strategy and needs to be adopted for further management. The Ahmedabad model of COVID-19 control was practiced during 3rd week of June 2020 onwards. Following implementation, cases started declining in Ahmedabad district whereas it showed an increasing trend in rest of Gujarat where it was not implemented. CONCLUSIONS: Cases with low viral load may be quarantined at home with standard precaution whereas cases with higher viral load need to be quarantined in institutions (hospital or separate premises away from family).