J Res Health Sci. 2021 Jul 6;21(3):e00522. doi: 10.34172/jrhs.2021.55.
BACKGROUND: On chronic exposure, Lead (Pb) deposits in the skeletal system, replaces calcium ions, and alters the normal physiological processes, which in turn, lead to stunting, delayed fracture healing, and high resorption of collagen molecules. The present study aimed to assess the association of musculoskeletal pain and discomfort with bone turnover markers (BTMs) among long-term Pb-exposed workers.
STUDY DESIGN: A cross-sectional study.
METHODS: The study recruited 176 male Pb-exposed workers and 80 control subjects who were matched for age, gender, and socio-economic status. Blood lead levels (BLLs), bone growth markers, such as serum osteocalcin (OC), alkaline phosphatase (ALP), bone alkaline phosphatase (BAP), and bone resorption markers: serum pyridinoline (Pry), deoxypyridinoline (DPry), tartrate-resistant acid phosphatase-5b(TRACP-5b), and hydroxyproline in urine (HyP-U) of participants were investigated. Pain and discomfort in the musculoskeletal system were assessed using Nordic Musculoskeletal Questionnaire.
RESULTS: Pb-exposure was significantly associated with musculoskeletal discomfort of the lower back (P<0.001), upper back (P<0.001), and ankle/foot (P=0.011). Among bone formation markers, serum OC was significantly lower in musculoskeletal discomfort of elbows (P=0.033) and ankle/foot (P=0.042). Among bone resorption markers, serum DPry was significantly lower in musculoskeletal discomfort of the neck (P=0.049) and shoulders (P=0.023). HyP-U was significantly higher in musculoskeletal discomfort of shoulders (P=0.035) and lower back (P=0.036).
CONCLUSION: As evidenced by the obtained results, Pb-exposure was associated with musculoskeletal discomfort of the lower back, upper back, and ankle/foot. Lower bone formation (serum OC) marker was noted with musculoskeletal discomfort of elbows and ankle/foot. Furthermore, bone resorption markers were associated with musculoskeletal discomfort of the neck, shoulders, and lower back. The findings of the present study suggested that long-term Pb-exposure and BTMs were associated with musculoskeletal discomfort.
Evidence-Based Health Behavior Interventions for Cholera: Lessons from an Outbreak Investigation in India
Am J Trop Med Hyg. 2021 Oct 25:tpmd210625. doi: 10.4269/ajtmh.21-0625. Online ahead of print.
In rural India, since 2014, the Swachh Bharat Abhiyan (Clean India Mission) has ensured construction of more than 100 million toilets and is now focusing on reinforcement of sanitation behaviors. We report a cholera outbreak in a remote village in western India where open defecation was implicated in causation. A water pipeline was damaged in the vicinity of a stream flowing from a site of open defecation. Despite the availability of a toilet facility in the majority of households (75%), open defecation was widely practiced (62.8%). Many reported not washing hands with soap and water before eating (78.5%) and after defecation (61.1%). The study emphasizes the need for focused health behavior studies and evidence-based interventions to reduce the occurrence of cholera outbreaks. This could be the last lap in the path toward achieving Sustainable Development Goal 6, which aims to "ensure availability and sustainable management of water and sanitation for all."
A rare case of severe gastroenteritis caused by Aeromonas hydrophila after colectomy in a patient with anti-Hu syndrome: a case report
BMC Infect Dis. 2021 Oct 24;21(1):1097. doi: 10.1186/s12879-021-06784-3.
BACKGROUND: Aeromonas hydrophila is a gram-negative facultative anaerobic coccobacillus, which is an environmental opportunistic pathogen. A. hydrophila are involved in several infectious diseases such as gastroenteritis, septicemia and wound infections. However, gastroenteritis caused by Aeromonas spp. are rare and the clinical relevance of Aeromonas species in stool specimens is still under debate.
CASE PRESENTATION: Our case concerns a 32-year-old woman who presented at hospital with a worsening watery diarrhea and fever requiring intensive care. A cholera-like illness was diagnosed. The patient had a past history of an anti-Hu syndrome with a myenteric ganglionitis. A molecular multiplex RT-PCR (QIAstat-Dx Gastrointestinal Panel, QIAGEN) covering a broad spectrum of diverse gastrointestinal pathogens performed directly from the stool was negative but the stool culture revealed growth of A. hydrophila. Further investigations of the A. hydrophila strain in cell cultures revealed the presence of a cytotoxic enterotoxin.
CONCLUSIONS: Although A. hydrophila rarely causes gastroenteritis, Aeromonas spp. should be considered as a causative agent of severe gastroenteritis with a cholera-like presentation. This case highlights the need to perform culture methods from stool samples when PCR-based methods are negative and gastrointestinal infection is suspected.
Emerg Infect Dis. 2021 Nov;27(11):2927-2931. doi: 10.3201/eid2711.211144.
We describe the molecular epidemiology of cholera in South Africa during 2018-2020. Vibrio cholerae O1 sequence type (ST) 75 recently emerged and became more prevalent than the V. cholerae O1 biotype El Tor pandemic clone. ST75 isolates were found across large spatial and temporal distances, suggesting local ST75 spread.
J Infect Dis. 2021 Oct 20:jiab465. doi: 10.1093/infdis/jiab465. Online ahead of print.
Cholera remains a major contributor of diarrheal diseases and leads to substantial morbidity and mortality particularly in low socio- economic setting. Non-availability of National Cholera Control Plan in India, compounded by underreporting of cholera cases and deficient accurate cholera hotspot estimates has made cholera control a challenge.Obstacles in programmatic introduction of Oral Cholera Vaccine (OCV) lie within its infrastructure- stockpile, costing, distribution system, cold chain mechanism, vaccine logistics and lack of strengthened Adverse Event Following Immunization (AEFI) surveillance systems. Sustained political commitment along with sensitization of media people will also determine policy outcome of OCV introduction in India.
Euro Surveill. 2021 Oct;26(41). doi: 10.2807/1560-7917.ES.2021.26.41.2002041.
BackgroundVibrio spp. are aquatic bacteria that prefer warm seawater with moderate salinity. In humans, they can cause gastroenteritis, wound infections, and ear infections. During the summers of 2018 and 2019, unprecedented high sea surface temperatures were recorded in the German Baltic Sea.AimWe aimed to describe the clinical course and microbiological characteristics of Vibrio infections in Germany in 2018 and 2019.MethodsWe performed an observational retrospective multi-centre cohort study of patients diagnosed with domestically-acquired Vibrio infections in Germany in 2018 and 2019. Demographic, clinical, and microbiological data were assessed, and isolates were subjected to whole genome sequencing and antimicrobial susceptibility testing.ResultsOf the 63 patients with Vibrio infections, most contracted the virus between June and September, primarily in the Baltic Sea: 44 (70%) were male and the median age was 65 years (range: 2-93 years). Thirty-eight patients presented with wound infections, 16 with ear infections, six with gastroenteritis, two with pneumonia (after seawater aspiration) and one with primary septicaemia. The majority of infections were attributed to V. cholerae (non-O1/non-O139) (n = 30; 48%) or V. vulnificus (n = 22; 38%). Phylogenetic analyses of 12 available isolates showed clusters of three identical strains of V. vulnificus, which caused wound infections, suggesting that some clonal lines can spread across the Baltic Sea.ConclusionsDuring the summers of 2018 and 2019, severe heatwaves facilitated increased numbers of Vibrio infections in Germany. Since climate change is likely to favour the proliferation of these bacteria, a further increase in Vibrio-associated diseases is expected.
Effectiveness of hygiene kit distribution to reduce cholera transmission in Kasai-Oriental, Democratic Republic of Congo, 2018: a prospective cohort study
BMJ Open. 2021 Oct 14;11(10):e050943. doi: 10.1136/bmjopen-2021-050943.
INTRODUCTION: Household contacts of cholera cases are at a greater risk of Vibrio cholerae infection than the general population. There is currently no agreed standard of care for household contacts, despite their high risk of infection, in cholera response strategies. In 2018, hygiene kit distribution and health promotion was recommended by Médecins Sans Frontières for admitted patients and accompanying household members on admission to a cholera treatment unit in the Democratic Republic of Congo.
METHODS: To investigate the effectiveness of the intervention and risk factors for cholera infection, we conducted a prospective cohort study and followed household contacts for 7 days after patient admission. Clinical surveillance among household contacts was based on self-reported symptoms of cholera and diarrhoea, and environmental surveillance through the collection and analysis of food and water samples.
RESULTS: From 94 eligible households, 469 household contacts were enrolled and 444 completed follow-up. Multivariate analysis suggested evidence of a dose-response relationship with increased kit use associated with decreased relative risk of suspected cholera: household contacts in the high kit-use group had a 66% lower incidence of suspected cholera (adjusted risk ratio (aRR) 0.34, 95% CI 0.11 to 1.03, p=0.055), the mid-use group had a 53% lower incidence (aRR 0.47, 95% CI 0.17 to 1.29, p=1.44) and low-use group had 22% lower incidence (aRR 0.78, 95% CI 0.24 to 2.53, p=0.684), compared with household contacts without a kit. Drinking water contamination was significantly reduced among households in receipt of a kit. There was no significant effect on self-reported diarrhoea or food contamination.
CONCLUSION: The integration of a hygiene kit intervention to case-households may be effective in reducing cholera transmission among household contacts and environmental contamination within the household. Further work is required to evaluate whether other proactive localised distribution among patients and case-households or to households surrounding cholera cases can be used in future cholera response programmes in emergency contexts.
Climate Precursors of Satellite Water Marker Index for Spring Cholera Outbreak in Northern Bay of Bengal Coastal Regions
Int J Environ Res Public Health. 2021 Sep 28;18(19):10201. doi: 10.3390/ijerph181910201.
Cholera is a water-borne infectious disease that affects 1.3 to 4 million people, with 21,000 to 143,000 reported fatalities each year worldwide. Outbreaks are devastating to affected communities and their prospects for development. The key to support preparedness and public health response is the ability to forecast cholera outbreaks with sufficient lead time. How Vibrio cholerae survives in the environment outside a human host is an important route of disease transmission. Thus, identifying the environmental and climate drivers of these pathogens is highly desirable. Here, we elucidate for the first time a mechanistic link between climate variability and cholera (Satellite Water Marker; SWM) index in the Bengal Delta, which allows us to predict cholera outbreaks up to two seasons earlier. High values of the SWM index in fall were associated with above-normal summer monsoon rainfalls over northern India. In turn, these correlated with the La Niña climate pattern that was traced back to the summer monsoon and previous spring seasons. We present a new multi-linear regression model that can explain 50% of the SWM variability over the Bengal Delta based on the relationship with climatic indices of the El Niño Southern Oscillation, Indian Ocean Dipole, and summer monsoon rainfall during the decades 1997-2016. Interestingly, we further found that these relationships were non-stationary over the multi-decadal period 1948-2018. These results bear novel implications for developing outbreak-risk forecasts, demonstrating a crucial need to account for multi-decadal variations in climate interactions and underscoring to better understand how the south Asian summer monsoon responds to climate variability.
Increased human-animal interface & emerging zoonotic diseases: An enigma requiring multi-sectoral efforts to address
Indian J Med Res. 2021 May&Jun;153(5&6):577-584. doi: 10.4103/ijmr.IJMR_2971_20.
Increased human-animal interfaces impose threats on human life by creating scope for the emergence and resurgence of many infectious diseases. Over the last two decades, emergence of novel viral diseases such as SARS, influenza A/H1N1(09) pdm; MERS; Nipah virus disease; Ebola haemorrhagic fever and the current COVID-19 has resulted in massive outbreaks, epidemics and pandemics thereby causing profound losses of human life, health and economy. The current COVID-19 pandemic has affected more than 200 countries, reporting a global case load of 167,878,000 with 2 per cent mortality as on May 26, 2021. This has highlighted the importance of reducing human- animal interfaces to prevent such zoonoses. Rapid deforestation, shrinking of boundaries between human and animal, crisis for natural habitation, increasing demands for wildlife products and threat of extinction compounded by biodiversity narrowing compel to increased human-animal conflict and contact. Large quantities of animal waste generated due to animal agriculture may also allow rapid selection, amplification, dissemination of zoonotic pathogens and facilitate zoonotic pathogen adaptation and hinder host evolution for resistance. Public health system faces challenges to contain such epidemics due to inadequate understanding, poor preparedness, lack of interdisciplinary approach in surveillance and control strategy and deficient political commitments. Because the management measures are beyond the purview of health system alone, policy-level adaptation in the transdisciplinary issues are required, emphasizing the engagement of multiple stakeholders towards wildlife protection, alternative land use, community empowerment for natural resource management and regulation on business of wildlife products to ensure comprehensive one health practice.
Characteristics of Rotavirus, ETEC, and Vibrio Cholerae Among Under 2-year Children Attending an Urban Diarrheal Disease Hospital in Bangladesh
J Prim Care Community Health. 2021 Jan-Dec;12:21501327211049118. doi: 10.1177/21501327211049118.
BACKGROUND: Information on comparative clinical and host characteristics of under-2 children with watery diarrhea caused by rotavirus, Enterotoxigenic Escherichia coli (ETEC), and Vibrio cholerae as single pathogens is lacking. We sought to investigate the sociodemographic, clinical, and host characteristics of under-2 children hospitalized due to these pathogens.
METHODOLOGY: We conducted a hospital-based case-control study using the icddr,b Diarrheal Diseases Surveillance System. Children of either sex, <2 years with diarrhea, who attended the hospital during 2014 to 2018, constituted the study population. Stool specimens having a single pathogen like rotavirus, ETEC, or Vibrio cholerae constituted the cases and stool specimens having no detectable common enteropathogens comprised the controls. Multinomial logistic regression analysis was done where control was the reference group.
RESULTS: A total of 14 889 patients were enrolled, 6939 of whom were under-2 children, and 5245 (76%) constituted our study population. Among them 48% (n = 2532), 3% (n = 148) and 1% (n = 49) had rotavirus, ETEC, and Vibrio cholera, respectively. A control group (diarrhea without these 3 or Shigella, Salmonella, Aeromonas) accounted for 48% (n = 2516). In multinomial regression model, children with rotavirus (adjusted odds ratio [aOR], 1.36; 95% confidence interval [95% CI], 1.19-1.55) less often presented with dehydrating diarrhea compared to those with ETEC (aOR, 1.54; 95% CI, 1.05-2.26) and cholera (aOR, 2.25; 95% CI, 1.11-4.57). Rotavirus diarrhea was associated (aOR, 1.25; 95% CI, 1.07-1.46) with those who received antimicrobials prior to hospital admission and protectively associated with drinking tap water (aOR, 0.84; 95% CI, 0.73-0.95); however, ETEC diarrhea had protective association (aOR, 0.62; 95% CI, 0.43-0.92) with children who received antimicrobials prior to hospital admission and was associated with drinking tap water (aOR, 1.78; 95% CI, 1.19-2.66). Use of intravenous fluid was associated with cholera (aOR, 10.36; 95% CI, 4.85-22.16) and had protective association with rotavirus episodes (aOR, 0.64; 95% CI, 0.45-0.91).
CONCLUSIONS: Clinical presentations and host characteristics of rotavirus, ETEC, and Vibrio cholerae diarrhea differed from each other and the information may be helpful for clinicians for better understanding and proper management of these children.
Cohort profile: Indian Network of Population-Based Surveillance Platforms for Influenza and Other Respiratory Viruses among the Elderly (INSPIRE)
BMJ Open. 2021 Oct 7;11(10):e052473. doi: 10.1136/bmjopen-2021-052473.
PURPOSE: We describe here a multicentric community-dwelling cohort of older adults (>60 years of age) established to estimate incidence, study risk factors, healthcare utilisation and economic burden associated with influenza and respiratory syncytial virus (RSV) in India.
PARTICIPANTS: The four sites of this cohort are in northern (Ballabgarh), southern (Chennai), eastern (Kolkata) and western (Pune) parts of India. We enrolled 5336 participants across 4220 households and began surveillance in July 2018 for viral respiratory infections with additional participants enrolled annually. Trained field workers collected data about individual-level and household-level risk factors at enrolment and quarterly assessed frailty and grip strength. Trained nurses surveilled weekly to identify acute respiratory infections (ARI) and clinically assessed individuals to diagnose acute lower respiratory infection (ALRI) as per protocol. Nasal and oropharyngeal swabs are collected from all ALRI cases and one-fifth of the other ARI cases for laboratory testing. Cost data of the episode are collected using the WHO approach for estimating the economic burden of seasonal influenza. Handheld tablets with Open Data Kit platform were used for data collection.
FINDINGS TO DATE: The attrition of 352 participants due to migration and deaths was offset by enrolling 680 new entrants in the second year. All four sites reported negligible influenza vaccination uptake (0.1%-0.4%), low health insurance coverage (0.4%-22%) and high tobacco use (19%-52%). Ballabgarh had the highest proportion (54.4%) of households in the richest wealth quintile, but reported high solid fuel use (92%). Frailty levels were highest in Kolkata (11.3%) and lowest in Pune (6.8%). The Chennai cohort had highest self-reported morbidity (90.1%).
FUTURE PLANS: The findings of this cohort will be used to inform prioritisation of strategies for influenza and RSV control for older adults in India. We also plan to conduct epidemiological studies of SARS-CoV-2 using this platform.
Cholera risk in cities in Uganda: understanding cases and contacts centered strategy (3CS) for rapid cholera outbreak control
Pan Afr Med J. 2021 Jul 12;39:193. doi: 10.11604/pamj.2021.39.193.27794. eCollection 2021.
INTRODUCTION: in the recent past, cities in sub-Saharan Africa have reported serious cholera outbreaks that last for several months. Uganda is one of the African countries where cities are prone to cholera outbreaks. Studies on cholera in Bangladesh show increased risk of cholera for the immediate household members (contacts) yet the control interventions mainly target cases with little or no focus on contacts. This study aimed to describe the rapid control of cholera outbreaks in Kampala and Mbale cities, Uganda, using, "Cases and Contacts Centered Strategy (3CS)" that consisted of identification and treatment of cases, promotion of safe water, sanitation, hygiene (WaSH) and selective chemoprophylaxis for the contacts.
METHODS: a cross-sectional study was conducted in 2015-2016 in the Kampala and Mbale cities during cholera outbreaks. Cholera cases were treated and 816 contacts from 188 households were listed and given cholera preventive packages. Data were collected, cleaned, analysed and stored in spreadsheet. Comparison of categories was done using Chi-Square test.
RESULTS: a total of 58 and 41 confirmed cholera cases out of 318 and 153 suspected cases were recorded in Kampala and Mbale cities respectively. The outbreaks lasted for 41 days in both cities. Case fatality rates were high; 12.1% (5/41) for Mbale city and 1.7% (1/58) for Kampala city. Fifty-five percent (210/379) of stool samples were tested by culture to confirm V. choleraeO1. No contacts listed and given cholera preventive package developed cholera. Both sexes and all age groups were affected. In Kampala city, the males were more affected than the females in the age groups less than 14 years, p-value of 0.0097.
CONCLUSION: this study showed that by implementing 3CS, it was possible to rapidly control cholera outbreaks in Kampala and Mbale cities and no cholera cases were reported amongst the listed household contacts. The findings on 3CS and specifically, selective antibiotic chemoprophylaxis for cholera prevention, could be used in similar manner to oral cholera vaccines to complement the core cholera control interventions (disease surveillance, treatment of cases and WaSH). However, studies are needed to guide such rollout and to understand the age-sex differences in Kampala city.
Drought-related cholera outbreaks in Africa and the implications for climate change: a narrative review
Pathog Glob Health. 2021 Oct 2:1-10. doi: 10.1080/20477724.2021.1981716. Online ahead of print.
Africa has historically seen several periods of prolonged and extreme droughts across the continent, causing food insecurity, exacerbating social inequity and frequent mortality. A known consequence of droughts and their associated risk factors are infectious disease outbreaks, which are worsened by malnutrition, poor access to water, sanitation and hygiene and population displacement. Cholera is a potential causative agent of such outbreaks. Africa has the highest global cholera burden, several drought-prone regions and high levels of inequity. Despite this, research on cholera and drought in Africa is lacking. Here, we review available research on drought-related cholera outbreaks in Africa and identify a variety of potential mechanisms through which these outbreaks occurred, including poor access to water, marginalization of refugees and nomadic populations, expansion of informal urban settlements and demographic risks. Future climate change may alter precipitation, temperature and drought patterns, resulting in more extremes, although these changes are likely to be spatially heterogeneous. Despite high uncertainty in future drought projections, increases in drought frequency and/or durations have the potential to alter these related outbreaks into the future, potentially increasing cholera burden in the absence of countermeasures (e.g. improved sanitation infrastructure). To enable effective planning for a potentially more drought-prone Africa, inequity must be addressed, research on the health implications of drought should be enhanced, and better drought diplomacy is required to improve drought resilience under climate change.
High-throughput low-cost nl-qPCR for enteropathogen detection: A proof-of-concept among hospitalized patients in Bangladesh
PLoS One. 2021 Oct 1;16(10):e0257708. doi: 10.1371/journal.pone.0257708. eCollection 2021.
BACKGROUND: Diarrheal disease is a leading cause of morbidity and mortality globally, especially in low- and middle-income countries. High-throughput and low-cost approaches to identify etiologic agents are needed to guide public health mitigation. Nanoliter-qPCR (nl-qPCR) is an attractive alternative to more expensive methods yet is nascent in application and without a proof-of-concept among hospitalized patients.
METHODS: A census-based study was conducted among diarrheal patients admitted at two government hospitals in rural Bangladesh during a diarrheal outbreak period. DNA was extracted from stool samples and assayed by nl-qPCR for common bacterial, protozoan, and helminth enteropathogens as the primary outcome.
RESULTS: A total of 961 patients were enrolled; stool samples were collected from 827 patients. Enteropathogens were detected in 69% of patient samples; More than one enteropathogen was detected in 32%. Enteropathogens most commonly detected were enteroaggregative Escherichia coli (26.0%), Shiga toxin-producing E.coli (18.3%), enterotoxigenic E. coli (15.5% heat stable toxin positive, 2.2% heat labile toxin positive), Shigella spp. (14.8%), and Vibrio cholerae (9.0%). Geospatial analysis revealed that the median number of pathogens per patient and the proportion of cases presenting with severe dehydration were greatest amongst patients residing closest to the study hospitals."
CONCLUSIONS: This study demonstrates a proof-of-concept for nl-qPCR as a high-throughput low-cost method for enteropathogen detection among hospitalized patients.
J Med Microbiol. 2021 Sep;70(9). doi: 10.1099/jmm.0.001423.
Vibrio cholerae O1 is the aetiological agent of the severe diarrhoeal disease cholera. Annually, there are an estimated 1-4 million cholera cases worldwide and over 140 000 deaths. The primary mode of disease transmission is through the consumption of water or food contaminated with the bacterium. Although cholera patients can be treated effectively using rehydration therapy, the disease remains a major scourge in areas with limited access to clean water and proper sanitation. Its continued prevalence highlights the failure of socioeconomic policies leading to wealth disparities, fragile and dated public infrastructure, and lack of appropriate health surveillance.
Optimizing immunization schedules in endemic cholera regions: cost-effectiveness assessment of vaccination strategies for cholera control in Bangladesh
Vaccine. 2021 Oct 15;39(43):6356-6363. doi: 10.1016/j.vaccine.2021.09.044. Epub 2021 Sep 25.
This study is to examine the cost-effectiveness of deployment strategies of oral cholera vaccines (OCVs) in controlling cholera in Bangladesh. We developed a dynamic compartment model to simulate costs and health outcomes for 12 years for four OCVs deployment scenarios: (1) vaccination of children aged one and above with two doses of OCVs, (2) vaccination of population aged 5 and above with a single dose of OCVs, (3) vaccination of children aged 1-4 with two doses of OCVs; and (4) combined strategy of (2) and (3). We obtained all parameters from the literature and performed a cost-effectiveness analysis from both health systems and societal perspectives, in comparison with the base scenario of no vaccination.The incremental cost-effectiveness ratios (ICERs) for the four strategies from the societal perspective were $2,236, $2,250, $1,109, and $2,112 per DALY averted, respectively, with herd immunity being considered. Without herd immunity, the ICERs increased substantially for all four scenarios except for the scenario that vaccinates children aged 1-4 only. The major determinants of ICERs were the case fatality rate and the incidence of cholera, as well as the efficacy of OCVs. The projection period and frequency of administering OCVs would also affect the cost-effectiveness of OCVs. With the cut-off of 1.5 times gross domestic product per capita, the four OCVs deployment strategies are cost-effective. The combined strategy is more efficient than the strategy of vaccinating the population aged one and above with two doses of OCVs and could be considered in the resource-limited settings.
Clinical Characterization and Genomic Analysis of Samples from COVID-19 Breakthrough Infections during the Second Wave among the Various States of India
Viruses. 2021 Sep 7;13(9):1782. doi: 10.3390/v13091782.
From March to June 2021, India experienced a deadly second wave of COVID-19, with an increased number of post-vaccination breakthrough infections reported across the country. To understand the possible reason for these breakthroughs, we collected 677 clinical samples (throat swab/nasal swabs) of individuals from 17 states/Union Territories of the country who had received two doses (n = 592) and one dose (n = 85) of vaccines and tested positive for COVID-19. These cases were telephonically interviewed and clinical data were analyzed. A total of 511 SARS-CoV-2 genomes were recovered with genome coverage of higher than 98% from both groups. Analysis of both groups determined that 86.69% (n = 443) of them belonged to the Delta variant, along with Alpha, Kappa, Delta AY.1, and Delta AY.2. The Delta variant clustered into four distinct sub-lineages. Sub-lineage I had mutations in ORF1ab A1306S, P2046L, P2287S, V2930L, T3255I, T3446A, G5063S, P5401L, and A6319V, and in N G215C; Sub-lineage II had mutations in ORF1ab P309L, A3209V, V3718A, G5063S, P5401L, and ORF7a L116F; Sub-lineage III had mutations in ORF1ab A3209V, V3718A, T3750I, G5063S, and P5401L and in spike A222V; Sub-lineage IV had mutations in ORF1ab P309L, D2980N, and F3138S and spike K77T. This study indicates that majority of the breakthrough COVID-19 clinical cases were infected with the Delta variant, and only 9.8% cases required hospitalization, while fatality was observed in only 0.4% cases. This clearly suggests that the vaccination does provide reduction in hospital admission and mortality.
J Math Biol. 2021 Sep 24;83(4):41. doi: 10.1007/s00285-021-01672-5.
A nonlocal and delayed cholera model with two transmission mechanisms in a spatially heterogeneous environment is derived. We introduce two basic reproduction numbers, one is for the bacterium in the environment and the other is for the cholera disease in the host population. If the basic reproduction number for the cholera bacterium in the environment is strictly less than one and the basic reproduction number of infection is no more than one, we prove globally asymptotically stability of the infection-free steady state. Otherwise, the infection will persist and there exists at least one endemic steady state. For the special homogeneous case, the endemic steady state is actually unique and globally asymptotically stable. Under some conditions, the basic reproduction number of infection is strictly decreasing with respect to the diffusion coefficients of cholera bacteria and infectious hosts. When these conditions are violated, numerical simulation suggests that spatial diffusion may not only spread the infection from high-risk region to low-risk region, but also increase the infection level in high-risk region.
Indian J Public Health. 2021 Jul-Sep;65(3):311-314. doi: 10.4103/ijph.IJPH_21_21.
Cholera is a diarrheal disease causing major health issue in developing countries where it is endemic and causes outbreaks. India ranks first with an estimated 675,188 number of cases and 20,256 number of deaths annually with one-third of its population at risk. The two broad approaches for cholera control are improving sanitation and vaccination. Now both live and killed oral vaccines are available. Live vaccines are advantageous in respect of intestinal colonization and rapid immune response and also lead to in vivo exposure of bacterial products leading to good immunological response against wild Vibrio cholerae infection. The three major delivery strategies which can be considered for the implementation of oral cholera vaccine are preemptive vaccination, reactive vaccinations, and National Immunization Program. We propose the use of cholera live oral vaccines for achieving control of this disease by repeated vaccination of the susceptible population in a series of pulses to control it from the entire population.
Antimicrobial Resistance in endemic enteric infections in Kenya and the region, and efforts towards addressing the challenges
J Infect Dis. 2021 Sep 22:jiab457. doi: 10.1093/infdis/jiab457. Online ahead of print.
Resistance to commonly available antimicrobials is a major threat to the fight against endemic bacterial diseases in sub-Saharan Africa (SSA), with majority of the population unable to afford alternative effective antimicrobial options for management of these diseases. Diseases such as typhoid, cholera and invasive non-typhoidal salmonella (NTS) are among the key enteric infections endemic in most parts of SSA, especially in displaced populations and among the urban populations living in overcrowded informal settlements. Here, we explore the prevalence and the genomic epidemiology of these infections and the growing problem of multidrug resistance (MDR) including emerging resistance to the last line of treatment for these infections. Prevalence rates to commonly available antimicrobials including ampicillin, chloramphenicol, co-trimoxazole and tetracycline, now range between 65-80%, while 15-20% of recently studied isolates show reduced susceptibility to fluoroquinolones and emerging resistance to extended spectrum beta-lactams (ESBLs) mediated by the CTX-M-15 gene carried on a highly mobile genetic element. The high prevalence of MDR isolates including resistance to reserve antibiotics, calls for enhanced control and management options. It will be important for governments in the region to enhance the implementation of National Action Plans as guided by the Global Action Plan championed by the World Health Organisation (WHO) to combat the threat of antimicrobial resistance. However, these efforts will require a strong commitment and enhanced at all different levels of healthcare in order to yield meaningful results. In addition, utilization of WHO approved vaccines in the short-to-medium term and improvement of water and sanitation in the long term will reduce burden of disease and AMR in the region.