Infectious Diseases of Poverty最新文献

Background: The ongoing transmission of the Middle East respiratory syndrome coronavirus (MERS-CoV) in the Middle East and its expansion to other regions are raising concerns of a potential pandemic. An in-depth analysis about both population and molecular epidemiology of this pathogen is needed.

Methods: MERS cases reported globally as of June 2020 were collected mainly from World Health Organization official reports, supplemented by other reliable sources. Determinants for case fatality and spatial diffusion of MERS were assessed with Logistic regressions and Cox proportional hazard models, respectively. Phylogenetic and phylogeographic analyses were performed to examine the evolution and migration history of MERS-CoV.

Results: A total of 2562 confirmed MERS cases with 150 case clusters were reported with a case fatality rate of 32.7% (95% CI: 30.9‒34.6%). Saudi Arabia accounted for 83.6% of the cases. Age of ≥ 65 years old, underlying conditions and ≥ 5 days delay in diagnosis were independent risk factors for death. However, a history of animal contact was associated with a higher risk (adjusted OR = 2.97, 95% CI: 1.10-7.98) among female cases < 65 years but with a lower risk (adjusted OR = 0.31, 95% CI: 0.18-0.51) among male cases ≥ 65 years old. Diffusion of the disease was fastest from its origin in Saudi Arabia to the east, and was primarily driven by the transportation network. The most recent sub-clade C5.1 (since 2013) was associated with non-synonymous mutations and a higher mortality rate. Phylogeographic analyses pointed to Riyadh of Saudi Arabia and Abu Dhabi of the United Arab Emirates as the hubs for both local and international spread of MERS-CoV.

Conclusions: MERS-CoV remains primarily locally transmitted in the Middle East, with opportunistic exportation to other continents and a potential of causing transmission clusters of human cases. Animal contact is associated with a higher risk of death, but the association differs by age and sex. Transportation network is the leading driver for the spatial diffusion of the disease. These findings how this pathogen spread are helpful for targeting public health surveillance and interventions to control endemics and to prevent a potential pandemic.

Background: Strongyloidiasis is the most neglected of the neglected tropical diseases (NTDs). The aim of this commentary is to describe the possible reasons why strongyloidiasis is so overlooked in Ethiopia, and shed light on better ways of control and elimination of the disease.

Main body: This commentary highlights three points why strongyloidiasis is the most neglected of the NTDs in Ethiopia. Firstly, lack of clear category within the NTDs resulted in omission of the disease from reports, intervention programs, and preventive chemotherapy guidelines. Secondly, magnitude of the disease is underestimated due to paucity of studies and low sensitivity of diagnostic methods coupled with asymptomatic nature of most of the infections. Finally, ivermectin (the drug of choice for treatment of strongyloidiasis) is not in use for control of the other soil-transmitted helminthiasis, nor is there ivermectin mass drug administration for control of strongyloidiasis. This might have created gap in control and elimination of the disease in Ethiopia and possibly elsewhere.

Conclusion: Strongyloidiasis appears to be the most neglected of the NTDs mainly due to nature of the infection, low sensitivity of the routine diagnostic tools and it's exclusion from strategic plans and intervention programs. Moreover, studies on strongyloidiasis should use sensitive diagnostic tools. Strongyloidiasis control and elimination programs should be based on reliable evidence of epidemiology of the disease in Ethiopia.

Background: A local coronavirus disease 2019 (COVID-19) case confirmed on June 11, 2020 triggered an outbreak in Beijing, China after 56 consecutive days without a newly confirmed case. Non-pharmaceutical interventions (NPIs) were used to contain the source in Xinfadi (XFD) market. To rapidly control the outbreak, both traditional and newly introduced NPIs including large-scale management of high-risk populations and expanded severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PCR-based screening in the general population were conducted in Beijing. We aimed to assess the effectiveness of the response to the COVID-19 outbreak in Beijing's XFD market and inform future response efforts of resurgence across regions.

Methods: A modified susceptible-exposed-infectious-recovered (SEIR) model was developed and applied to evaluate a range of different scenarios from the public health perspective. Two outcomes were measured: magnitude of transmission (i.e., number of cases in the outbreak) and endpoint of transmission (i.e., date of containment). The outcomes of scenario evaluations were presented relative to the reality case (i.e., 368 cases in 34 days) with 95% Confidence Interval (CI).

Results: Our results indicated that a 3 to 14 day delay in the identification of XFD as the infection source and initiation of NPIs would have caused a 3 to 28-fold increase in total case number (31-77 day delay in containment). A failure to implement the quarantine scheme employed in the XFD outbreak for defined key population would have caused a fivefold greater number of cases (73 day delay in containment). Similarly, failure to implement the quarantine plan executed in the XFD outbreak for close contacts would have caused twofold greater transmission (44 day delay in containment). Finally, failure to implement expanded nucleic acid screening in the general population would have yielded 1.6-fold greater transmission and a 32 day delay to containment.

Conclusions: This study informs new evidence that in form the selection of NPI to use as countermeasures in response to a COVID-19 outbreak and optimal timing of their implementation. The evidence provided by this study should inform responses to future outbreaks of COVID-19 and future infectious disease outbreak preparedness efforts in China and elsewhere.

Background: Cutaneous leishmaniasis (CL), endemic in Guatemala, mostly affects poor people living in the northern region. A national control program that includes surveillance, diagnose, and treatment offered free of cost by the Ministry of Health (MoH) has been in place since 2003. However, the incidence is increasing and treatment rates are not optimal, suggesting that current efforts are not being effective. This study aimed to understand barriers and facilitators of CL control in Guatemala as experienced and perceived by key stakeholders in order to comprehend what works well and does not and suggest evidence-informed interventions.

Methods: The study was conducted in the Cobán municipality, the most endemic of Guatemala, situated in the Department of Alta Verapaz. Data were collected during May and June 2019 via focus groups and semi-structured interviews with key stakeholders, including local and national health personnel and residents of four communities of the endemic region. Thematic and content analysis of the collected data was conducted using NVIVO.

Results: Three overarching issues hamper the effectiveness of current CL efforts: resource scarcity, treatment challenges, and knowledge-action gaps. Scarce economic resources from the MoH and community residents negatively impact incidence, detection of cases and treatment rates in that preventive action is insufficient and healthcare access is low. In addition, local health workers often lack specialized CL training and access to the national CL control guidelines. With regards to the population living in the study area, misunderstanding of disease causation, shame associated with CL lesions, treatment pain fear, and long (often uncertain) waiting times for diagnose and treatment negatively affect people's willingness to seek help, treatment adherence, and their trust on the healthcare provided.

Conclusions: Culturally sensitive CL preventive action must be developed. Given the scarce economic resources available for CL control in the country, the involvement of trained community health workers and the inclusion of thermotherapy as a treatment option is also advised. Other cost-effective actions include: ensuring all health workers receive CL training and have access to national CL control guidelines, improving national procurement system to avoid treatment shortages, and provision of motorized vehicles to increase active surveillance and treatment rates.

Background: The Upper West region of Ghana is mostly made up of rural communities and is highly endemic for lymphatic filariasis (LF), with a significant burden of disability due to lymphedema and hydrocele. The aim of this paper is to describe an enhanced, evidence-based cascading training program for integrated lymphedema management in this region, and to present some initial outcomes.

Main text: A baseline evaluation in the Upper West Region was carried out in 2019. A cascaded training program was designed and implemented, followed by a roll-out of self-care activities in all 72 sub-districts of the Upper West Region. A post implementation evaluation in 2020 showed that patients practiced self-care more frequently and with more correct techniques than before the training program; they were supported in this by health staff and family members.

Conclusions: Self-care for lymphedema is feasible and a program of short workshops in this cascaded training program led to significant improvements. Efforts to maintain momentum and sustain what has been achieved so far, will include regular training and supervision to improve coverage, the provision of adequate resources for limb care at home, and the maintenance of district registers of lymphedema cases, which must be updated regularly.

Background: Tuberculosis (TB) prevention through the use of preventive treatment is a critical activity in the elimination of TB. In multiple settings, limited staffing has been identified as a barrier to managing preventive treatment for TB contacts. This study aims to determine how health center staffing, service type, and TB caseload affects implementation of isoniazid preventive therapy (IPT) for TB contacts in southern Lima.

Methods: We conducted an ecological study in 2019 in southern Lima, Peru. Through the review of medical records, we identified contacts of TB patients who initiated IPT during 2016-2018, and who were 0-19 years old, the age group eligible for IPT according to Peruvian guidelines. We assessed bivariate associations between health center characteristics (numbers of physicians and nurses, types of services available, annual TB caseload) and IPT initiation and completion using binomial logistic regression.

Results: Among 977 contacts, 69% took more than a week to start IPT and 41% did not complete IPT. For those who successfully completed IPT, 58% did not complete full medical follow-up. There was no significant difference in IPT completion or adherence based on whether health centers had more physicians and nurses, more comprehensive services, or higher TB caseloads. Among contacts, female sex was associated with delay in initiating IPT (P = 0.005), age 5-19 years old was associated with completion of IPT (P = 0.025) and age < 5 years old was associated with completion of clinical evaluations (P = 0.041).

Conclusions: There are significant gaps in IPT implementation in health centers of southern Lima, Peru, but insufficient staffing of health centers may not be responsible. Further research is needed to identify how IPT implementation can be improved, potentially through improving staff training or monitoring and supervision.

Background: Shanghai had a local outbreak of COVID-19 from January 21 to 24. Timely and precise strategies were taken to prevent further spread of the disease. We discussed and shared the experience of COVID-19 containment in Shanghai.

Process: The first two patients worked at two hospitals but no staff from the two hospitals were infected. The suspected case and his two close contacts were confirmed to be infected within 12 h. The testing rate of individuals was low. The scope of screening was minimized to two related districts and the close contact tracing was completed within 12 h, which were precise and cost-effective.

Conclusions: Active monitoring, precise epidemiological investigation and timely nucleic acid testing help discover new cases, minimize the scope of screening, and interrupt the transmission.

Background: Information on the prevalence and resistance spectrum of nontuberculous mycobacteria (NTM) in China is mainly based on regional or local data. To estimate the proportion of NTM cases in China, a national survey of NTM pulmonary disease was carried out based on acid-fast positive sputum samples collected in 2013.

Methods: Sputum samples collected from enrolled presumptive cases in 72 nationwide tuberculosis surveillance sites from the 31 provinces in the mainland of China were cultured using L-J medium at the National tuberculosis reference laboratory (NTRL). MALDI-TOF MS identified the species of re-cultured strains, and minimal inhibitory concentrations (MICs) were determined to evaluate the drug susceptibility of NTM isolates. Data analysis used statistical software SPSS version 22.0 for Windows statistical package.

Results: Of 4917 mycobacterial isolates cultured, 6.4% [317/4917, 95% confidence interval (CI) 5.8%-7.2%] were confirmed as NTM, among which 7.7% (287/3709, 95% CI 6.9%-8.6%) were from the southern region. In inland and coastal China, 87.7% (95% CI 78.7%-93.2%) and 50.0% (95% CI 43.7%-56.3%) of isolates, respectively, were slow-growing mycobacteria (SGM), with the remaining rapid growing mycobacteria (RGM). A total of 29 species were detected, Mycobacterium abscessus had higher clarithromycin-inducible resistance rates than M. massiliense (65.67% vs 2.22%). M. kansasii presented lower resistance rates in linezolid and moxifloxacin than M. avium-intracellulare complex (3.23% vs 66.67%, 0 vs 47.22%) and other SGM (3.23% vs 38%, 0 vs 26%).

Conclusions: More NTM pulmonary disease was observed in the south and coastal China (P < 0.01). SGM was widely distributed, and more RGM are present in southern and coastal China (P < 0.01). The antimicrobial resistance spectrum of different NTM species was significantly different and accurate species identification would be facilitated to NTM pulmonary disease treatment.

Background: Mosquito-based arbovirus surveillance can serve as an early warning in evaluating the status of mosquito-borne virus prevalence and thus prevent local outbreaks. Although Tengchong County in Yunnan Province-which borders Myanmar-is abundant and diverse in mosquitoes, very few mosquito-based arbovirus investigations have been conducted in the recent decade. Herein, this study aims to evaluate the presence and the diffusion of mosquito-borne pathogens, currently prevalent in this region.

Methods: We collected 9486 mosquitoes, representing eight species, with Culex tritaeniorhynchus and Anopheles sinensis as the dominant species, during high mosquito activity seasons (July-October) in Tengchong, in 2018. Samples collected from 342 pools were tested using reverse-transcription PCR to determine the species, distribution, and infection rates of virus and parasite, and further analyze their genotypes, phylogenetic relationships, infection rate, and potential pathogenicity.

Results: Fifteen Japanese encephalitis virus (JEV) strains from Cx. tritaeniorhynchus pools were detected. Seven strains of insect-specific flaviviruses (ISFVs), including two Aedes flavivirus (AeFV) and Yunnan Culex flavivirus strains each, one Culex theileri flavivirus, Yamadai flavivirus (YDFV) and Anopheles-associated flavivirus (AAFV) strains each were detected in Aedes albopictus, Cx. tritaeniorhynchus, Cx. vagans, Cx. pseudovihnui, and An. sinensis pools, respectively. The whole-genome was successfully amplified in one strain of JEV and AeFV each. Phylogenetic analysis using the E gene placed all the newly detected JEV strains into the GI-b genotype. They showed highly nucleotide identities, and were most closely related to the strain detected in Tengchong in 2010. The comparison of the E protein of JEV strains and vaccine-derived strain, showed six amino residue differences. The bias-corrected maximum likelihood estimation values (and 95% confidence interval) for JEV in Cx. tritaeniorhynchus collected in Tengchong in 2018 were 2.4 (1.4-3.9).

Conclusions: A potential Japanese encephalitis epidemic focus with the abundance of host mosquitoes and high JEV infection rate was observed in Tengchong. In addition, at least five species of ISFVs co-circulate in this area. This study highlights the importance of widespread and sustained mosquito-based arbovirus surveillance in local areas to prevent the transmission of JEV, and other emerging/re-emerging mosquito-borne pathogens.