MedNexus
2021年 · 第10卷第02期
MedNexus
Malaria was once one of the most serious public health problems in China, with more than 30 million malaria cases annually before 1949. However, the disease burden has sharply declined and the epidemic areas has shrunken after the implementation of an integrated malaria control and elimination strategy, especially since 2000. Till now, China has successfully scaled up its efforts to become malaria-free and is currently being evaluated for malaria-free certification by the WHO. In the battle against malaria, China’s efforts have spanned generations, reducing from an incidence high of 122.9/10 000 (6.97 million cases) in 1954 to 0.06/10 000 (7855 cases) in 2010. In 2017, for the first time, China reached zero indigenous case of malaria, putting the country on track to record three consecutive years of zero transmission by 2020, accoding to the National Malaria Elimination Action Plan (2010-2020). China’s efforts to eliminate malaria is impressive, and the country is dedicated to sharing its lessons learned in malaria elimination-including, but not limited to, the application of novel genetics-based approaches—with other nations through new initiatives. China will promote international relationships and establish collaborative platforms on a wide range of topics in roughly 65 countries, including 20 African nations. China’s experience in applying innovative genetics-based approaches and tools to characterize malaria parasite populations, including surveillance of markers related to drug resistance, categorization of cases as indigenous or imported, and objective identification of the likely sources of infections to inform efforts towards malaria control and elimination in Africa could offer game-changing results when applied to settings with ongoing transmission.
As one of the non-pharmacological interventions to control the transmission of COVID-19, determining the quarantine duration is mainly based on the accurate estimates of the incubation period. However, patients with coarse information of the exposure date, as well as infections other than the symptomatic, were not taken into account in previously published studies. Thus, by using the statistical method dealing with the interval-censored data, we assessed the quarantine duration for both common and uncommon infections. The latter type includes the presymptomatic, the asymptomatic and the recurrent test positive patients.
As of 10 December 2020, information on cases have been collected from the English and Chinese databases, including Pubmed, Google scholar, CNKI (China National Knowledge Infrastructure) and Wanfang. Official websites and medias were also searched as data sources. All data were transformed into doubly interval-censored and the accelerated failure time model was applied. By estimating the incubation period and the time-to-event distribution of worldwide COVID-19 patients, we obtain the large percentiles for determining and suggesting the quarantine policies. For symptomatic and presymptomatic COVID-19 patients, the incubation time is the duration from exposure to symptom onset. For the asymptomatic, we substitute the date of first positive result of nucleic acid testing for that of symptom onset. Furthermore, the time from hospital discharge or getting negative test result to the positive recurrence has been calculated for recurrent positive patients.
A total of 1920 laboratory confirmed COVID-19 cases were included. Among all uncommon infections, 34.1% (n = 55) of them developed symptoms or were identified beyond fourteen days. Based on all collected cases, the 95th and 99th percentiles were estimated to be 16.2 days (95% CI 15.5-17.0) and 22.9 days (21.7-24.3) respectively. Besides, we got similar estimates based on merely symptomatic and presymptomatic infections as 15.1 days (14.4-15.7) and 21.1 days (20.0-22.2).
There are a certain number of infected people who require longer quarantine duration. Our findings well support the current practice of the extended active monitoring. To further prevent possible transmissions induced and facilitated by such infectious outliers after the 14-days quarantine, properly prolonging the quarantine duration could be prudent for high-risk scenarios and in regions with insufficient test resources.
Sexual transmission among men who have sex with men (MSM) is the dominant route of HIV transmission in China. Extensive use of geosocial networking (GSN) smartphone application (app) has dramatically changed the pattern of sexual behaviors and HIV risk among MSM, but data on HIV incidence and the changing risk behaviors of GSN app-using MSM are limited. We aims to assess the HIV incidence and its correlates among gay GSN app-using MSM in China.
We constructed an open cohort which was initiated and maintained using a GSN app to assess the HIV incidence among app-using MSM, recruited from June 2017 to December 2018. MSM completed an online questionnaire on their sociodemographic characteristics, sexual behaviors, recreational drug use and sexually transmitted infections status. Then each man had an HIV test, and those tested negatives were enrolled into the cohort. Participants completed follow-ups with additional HIV tests though the app during the study period, and were censored at HIV seroconversion or study end date. HIV incidence was calculated by dividing the sum of observed HIV seroconversions by the observed person-time. Univariate (Chi-square test and Fisher’s exact test) and multivariate (proportional hazards regression) analyses were used to examine correlates of HIV incidence.
A total of 6957 HIV negative MSM were enrolled in the open cohort, 37 seroconversions occurred among 1937 men contributing 1065 observed person-years: HIV incidence was 3.47 per 100 person-years [95% confidence interval (CI): 2.37-4.57]. More than five sexual partners [hazard ratio (HR) = 2.65, 95% CI: 1.04-6.67], and sex with HIV positive partners (HR = 3.82, 95% CI: 1.16-12.64) in the preceding six months were positively associated with HIV seroconversion. Consistent condom use for anal sex (HR = 0.27, 95% CI: 0.07-0.96), and reporting insertive anal sex only (HR = 0.23, 95% CI: 0.08-0.62) in the preceding six months were protective factors for HIV seroconversion.
Tailored interventions targeting app-using MSM are urgently needed given their high risk of HIV. As a new tool for accessing MSM at higher HIV risk, GSN smartphone app could play an important role in HIV research among MSM.
Cystic echinococcosis is one of the most severe helminth zoonosis with a drastic impact on human health and livestock industry. Investigating optimal control strategy and assessing the crucial factors are essential for developing countermeasures to mitigate this disease.
Two compartment models were formulated to study the dynamics of cystic echinococcosis transmission, to evaluate the effectiveness of various control measures, and to find the optimal control strategy. Sensitive analyses were conducted by obtaining PRCCs and contour plot was used to evaluate the effect of key parameters on the basic reproduction number. Based on forward-backward sweep method, numerical simulations were employed to investigate effects of key factors on the transmission of cystic echinococcosis and to obtain the optimal control strategy.
The food resources of stray dog and invalid sheep vaccination rate, which are always neglected, were significant to the transmission and control of cystic echinococcosis. Numerical simulations suggest that, the implementation of optimal control strategy can significantly reduce the infections. Improving the cost of health education and domestic dog deworming could not decrease human infections.
Our study showed that only a long-term use of the optimal control measures can eliminate the disease. Meanwhile, during the intervention, sheep vaccination and stray dogs disposing should be emphasized ahead of domestic dogs deworming to minimize the control cost. Simultaneously reducing other wild intermediate hosts and strengthening the sheep vaccination as well as disposing the stray dogs would be most effective.
The ongoing coronavirus disease 2019 (COVID-19) pandemic has put a strain on health systems globally. Although Africa is the least affected region to date, it has the weakest health systems and an exponential rise in cases as has been observed in other regions, is bound to overwhelm its health systems. Early detection and isolation of suspected and confirmed COVID-19 cases are pivotal to the prevention and control of the pandemic. The World Health Organization (WHO) recommends that all laboratory-confirmed cases should be isolated and treated in a health care facility; however, where this is not possible due to the health system capacity, patients can be isolated in re-purposed facilities or at home. An already very apparent future challenge for Africa is facility-based isolation of COVID-19 cases, given the already limited health infrastructure and health workforce, and the risk of nosocomial transmission. Use of repurposed facilities requires additional resources, including health workers. Home isolation, on the other hand, would be a challenge given the poor housing, overcrowding, inadequate access to water and sanitation, and stigma related to infectious disease that is prevalent in many African societies. Conflict settings on the continent pose an additional challenge to the prevention and control of COVID-19 with the resultant population displacements in overcrowded camps where access to social services is limited. These unique cultural, social, economic and developmental differences on the continent, call for a tailored approach to COVID-19 case management strategies. This article proposes three broad case management strategies based on the transmission scenarios defined by WHO, and the criteria and package of care for each option, for consideration by policy makers and governments in African countries. Moving forward, African countries should generate local evidence to guide the development of realistic home-grown strategies, protocol and equipment for the management of COVID-19 cases on the continent.
The End Tuberculosis (TB) Strategy of the World Health Organization highlights the need for patient-centered care and social protection measures that alleviate the financial hardships faced by many TB patients. In China, TB treatments are paid for by earmarked government funds, social health insurance, medical assistance for the poor, and out-of-pocket payments from patients. As part of Phase III of the China-Gates TB project, this paper introduces multi-source financing of TB treatment in the three provinces of China and analyzes the challenges of moving towards universal coverage and its implications of multi-sectoral engagement for TB care.
The new financing policies for TB treatment in the three provinces include increased reimbursement for TB outpatient care, linkage of TB treatment with local poverty alleviation programs, and use of local government funds to cover some costs to reduce out-of-pocket expenses. However, there are several challenges in reducing the financial burdens faced by TB patients. First, medical costs must be contained by reducing the profit-maximizing behaviors of hospitals. Second, treatment for TB and multi-drug resistant TB (MDR-TB) is only available at county hospitals and city or provincial hospitals, respectively, and these hospitals have low reimbursement rates and high co-payments. Third, many patients with TB and MDR-TB are at the edge of poverty, and therefore ineligible for medical assistance, which targets extremely poor individuals. In addition, the local governments of less developed provinces often face fiscal difficulties, making it challenging to use of local government funds to provide financial support for TB patients. We suggest that stakeholders at multiple sectors should engage in transparent and responsive communications, coordinate policy developments, and integrate resources to improve the integration of social protection schemes.
The Chinese government is examining the establishment of multi-source financing for TB treatment by mobilization of funds from the government and social protection schemes. These efforts require strengthening the cooperation of multiple sectors and improving the accountability of different government agencies. All key stakeholders must take concrete actions in the near future to assure significant progress toward the goal of alleviating the financial burden faced by TB and MDR-TB patients.
Severe hepatosplenic complications arise in patients with chronic Schistosoma mansoni infection after heavy exposure to disease agents in endemic areas. These complications are rarely reported and, hence, underestimated.
We report on eight patients with severe morbidity associated with S. mansoni infection in Ituri Province, northeastern Democratic Republic of Congo (DRC). The patients were identified during a community-based survey in 2017; one patient was seen at the district hospital. After taking the patients’ history, a clinical examination and an abdominal ultrasonographical examination were performed. S. mansoni infection was diagnosed in fecal (Kato-Katz technique) and urine (point-of-case circulating cathodic antigen test) samples. These eight patients with severe intestinal and hepatosplenic complications were identified from four villages with high S. mansoni infection prevalence and related morbidity. The patients’ ages ranged from 19 to 57 years; four patients were women. Three patients reported hematemesis. Two patients were severely anemic. All patients reported non-specific abdominal symptoms, such as diarrhea (six patients), abdominal pain (seven patients), and blood in the stool (five patients), as well as weight loss (two patients). Abdominal ultrasonography revealed ascites in four patients. All patients had portal hypertension with hepatomegaly (seven patients) or splenomegaly (five patients). Of the six patients with a discernable liver parenchyma pattern, five displayed pattern F and three patient displayed pattern E. Liver parenchyma was not visible for two patients with severe ascites. An S. mansoni infection was confirmed in six patients, with infection intensity ranging from light to heavy. All S. mansoni positive patients were treated with praziquantel (40 mg/kg body weight) and referred to the district hospital for follow-up. One patient with severe ascites died two weeks after we saw her. Due to security and accessibility reasons, the villages could not be visited again and the patients were lost to follow-up.
Our observations of patients with severe schistosomiasis document the severe degree of endemicity of S. mansoni in the province and suggest an urgent need for adequate schistosomiasis control measures that target vulnerable population groups and address severe complications.
The prevalence of human brucellosis in Qinghai Province of China has been increasing rapidly, with confirmed cases distributed across 31 counties. However, the epidemiology of brucellosis transmission has not been fully elucidated. To characterize the infecting strains isolated from humans, multiple-locus variable-number tandem repeats analysis (MLVA) and whole-genome single-nucleotide polymorphism (SNP)-based approaches were employed.
Strains were isolated from two males blood cultures that were confirmed Brucella melitensis positive following biotyping and MLVA. Genomic DNA was extracted from these two strains, and whole-genome sequencing was performed. Next, SNP-based phylogenetic analysis was performed to compare the two strains to 94 B. melitensis strains (complete genome and draft genome) retrieved from online databases.
The two Brucella isolates were identified as B. melitensis biovar 3 (QH2019001 and QH2019005) following conventional biotyping and were found to have differences in their variable number tandem repeats (VNTRs) using MLVA-16. Phylogenetic examination assigned the 96 strains to five genotype groups, with QH2019001 and QH2019005 assigned to the same group, but different subgroups. Moreover, the QH2019005 strain was assigned to a new subgenotype, IIj, within genotype II. These findings were then combined to determine the geographic origin of the two Brucella strains.
Utilizing a whole-genome SNP-based approach enabled differences between the two B. melitensis strains to be more clearly resolved, and facilitated the elucidation of their different evolutionary histories. This approach also revealed that QH2019005 is a member of a new subgenotype (IIj) with an ancient origin in the eastern Mediterranean Sea.
本期目次
