2017年 · 第06卷第05期

In the three decades since the first reported case of Ebola virus, most known index cases have been consistently traced to the hunting of "bush meat", and women have consistently recorded relatively high fatality rates in most catastrophic outbreaks. This paper discusses Ebola-related risk factors, which constantly interact with cultural values, and provides an insight into the link between gender and the risk of contracting infectious diseases, using Ebola virus as an example within Africa.

A comprehensive search of the literature was conducted using the PubMed, Ovid Medline and Global Health CABI databases as well as CAB Abstracts, including gray literature. We used a descriptive and sex- and gender-based analysis to revisit previous studies on Ebola outbreaks since 1976 to 2014, and disaggregated the cases and fatality rates according to gender and the sources of known index cases based on available data.

In total, approximately 1530 people died in all previous Ebola outbreaks from 1976 to 2012 compared with over 11,310 deaths from the 2014 outbreak. Women's increased exposure can be attributed to time spent at home and their responsibility for caring for the sick, while men's increased vulnerability to the virus can be attributed to their responsibility for caring for livestock and to time spent away from home, as most known sources of the index cases have been infected in the process of hunting. We present a conceptual model of a circle of interacting risk factors for Ebola in the African context.

There is currently no evidence related to biological differences in female or male sex that increases Ebola virus transmission and vulnerability; rather, there are differences in the level of exposure between men and women. Gender is therefore an important risk factor to consider in the design of health programs. Building the capacity for effective risk communication is a worthwhile investment in public and global health for future emergency responses.

Echinococcosis is a serious, zoonotic, parasitic disease with worldwide distribution. According to a epidemiological survey in 2012 in China, there are 20,000 infected patients and more than 50 million people at the risk. As the dog is the main, definitive host, the Government of China encourages monthly praziquantel treatment of every dog. However, this is difficult to achieve in geographically challenging areas, such as the Tibetan plateau, where there are also many dogs without owners. To overcome these problems, we investigated the transmission blocking capacity of a slow-release formulation of praziquantel administered by subcutaneous injection.

The impact of a slow-release preparation of two pharmacokinetically stereoselective praziquantel enantiomers, i.e., R-(-)-praziquantel (R-PZQ) and S-(+)-praziquantel (S-PZQ) absorbed into a biodegradable polymer was studied in beagle dogs (N = 6). The preparation was given by subcutaneous injection using a single dose of 100 mg/kg. Chiral-selective, high-performance liquid chromatography (HPLC) and high-resolution mass spectrometry (HRMS) were applied to measure the praziquantel enantiomers in the plasma of the dogs. The lower limit for estimating plasma concentrations accurately for R-PZQ was 4 ng/ml and for S-PZQ 20 ng/ml. The pharmacokinetic parameters were calculated by a noncompartmental analysis model using Drug Analyze System (DAS) software 2.0. The SPSS 19.0 software was used for statistical analysis, and the statistical comparison between enantiomers was assessed using the two-tailed t-test.

Two hours after administration, peak concentrations of R-PZQ and S-PZQ: 321 + 26 and 719 + 263 ng/ml, respectively, were achieved. After 180 days, the average plasma concentration of R-PZQ in the six dogs had decreased to 13 ng/ml. The average concentration value of S-PZQ was higher than that of R-PZQ in the first 90-day period but fell afterwards and could not be accurately estimated when dropping below 20 ng/ml (the lower methodological limit for this enantiomer). Taking all the dogs into account, the average maximum concentration (Cmax) of S-PZQ in plasma over the first 3 months was higher than that of R-PZQ by 114.0% (P < 0.05), while the average mean retention time (MRT) of R-PZQ in plasma was higher than that of S-PZQ by 96.3% (P < 0.05).

Praziquantel given as an in situ slow-release formulation by subcutaneous injection resulted in concentrations of the active principle in beagle dogs, which should be capable of resisting new Echinococcus infections for at least 6 months. The new formulation of praziquantel represents a potential, alternative way of presenting medication against tapeworm infections in dogs.

As part of the WHO End TB strategy, national tuberculosis (TB) programs increasingly aim to engage all private and public TB care providers. Engagement of communities, civil society organizations and public and private care provider is the second pillar of the End TB strategy. In Myanmar, this entails the public-public and public-private mix (PPM) approach. The public-public mix refers to public hospital TB services, with reporting to the national TB program (NTP). The public-private mix refers to private general practitioners providing TB services including TB diagnosis, treatment and reporting to NTP. The aim of this study was to assess whether PPM activities can be scaled-up nationally and can be sustained over time.

Using 2007-2014 aggregated program data, we collected information from NTP and non-NTP actors on 1) the number of TB cases detected and their relative contribution to the national case load; 2) the type of TB cases detected; 3) their treatment outcomes.

The total number of TB cases detected per year nationally increased from 133,547 in 2007 to 142,587 in 2014. The contribution of private practitioners increased from 11 % in 2007 to 18% in 2014, and from 1.8% to 4.6%for public hospitals. The NTP contribution decreased from 87% in 2007 to 77% in 2014. A similar pattern was seen in the number of new smear (+) TB cases (31% of all TB cases) and retreatment cases, which represented 7.8% of all TB cases. For new smear (+) TB cases, adverse outcomes were more common in public hospitals, with more patients dying, lost to follow up or not having their treatment outcome evaluated. Patients treated by private practitioners were more frequently lost to follow up (8%). Adverse treatment outcomes in retreatment cases were particularly common (59%) in public hospitals for various reasons, predominantly due to patients dying (26%) or not being evaluated (10%). In private clinics, treatment failure tended to be more common (8%).

The contribution of non-NTP actors to TB detection at the national level increased over time, with the largest contribution by private practitioners involved in PPM. Treatment outcomes were fair. Our findings confirm the role of PPM in national TB programs. To achieve the End TB targets, further expansion of PPM to engage all public and private medical facilities should be targeted.

The People's Republic of China (P.R. China) is the presumptive home range of the rat lungworm Angiostrongylus cantonensis, a major aetiological agent of human eosinophilic meningitis. We present a study of the genetic variation of A. cantonensis in P.R. China. Our aim was to deepen the current knowledge pertaining to its origin and global spread from a molecular perspective.

Adult A. cantonensis were collected in the frame of a national survey and identified based on morphological criteria. Polymerase chain reaction (PCR) was employed to amplify the target DNA sequences (cytochrome c oxidase subunit I (cox1), nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nadl) and internal transcribed spacer (ITS)). The PCR product of coxl was directly submitted to sequencing, while clone sequencing was used for nadl and ITS. The identity of the samples was verified by comparing the sequences to those of accepted A. cantonensis specimens. The specific composition of substitutions in each gene was analysed, and the genotypes were compared based on the complete coxl, nadl and ITS genes.

We characterised the complete mitochondrial genes coxl and nadl of 130 specimens and obtained 357nuclear sequences containing two complete ITS (ITS1 and ITS2) and 5.8S rRNA of the same samples. All specimens were genetically confirmed as A. cantonensis. Two major groups (i.e. I and II) were identified according to the phylogeny of coxl sequences. Group I could be further categorised into six distinct clades. Almost half of the specimens (47.7%) belong to the clade la and 22.3% to the group II. The former was widely distributed across the study region. A variable number of repeat units in three microsatellites was observed, resulting in considerable length variation in ITS. Intragenomic variation of ITS sequences was found in a large proportion of the samples. Genotyping showed a striking difference between mitochondrial DNA and ITS.

Our results demonstrate that A. cantonensis is the only rat lungworm species in P.R. China and shows high genetic diversity. Results of diversity and genotyping of A. cantonensis can be impacted by the sequencing strategy and biomarker. Although ITS may be a valuable marker for interspecific identification, it is not suitable for studying the intraspecific variation of A. cantonensis due to its high intragenomic variation and current challenges for direct sequencing.

Acute human African trypanosomiasis (rHAT) caused by Trypanosoma brucei rhodesiense is associated with high mortality and is fatal if left untreated. Only a few studies have examined the psychological, social and economic impacts of rHAT. In this study, mixed qualitative and quantitative research methods were used to evaluate the socio-economic impacts of rHAT in Mambwe, Rufunsa, Mpika and Chama Districts of Zambia.

Individuals diagnosed with rHAT from 2004 to 2014 were traced using hospital records and discussions with communities. Either they, or their families, were interviewed using a structured questionnaire and focus group discussions were conducted with affected communities. The burden of the disease was investigated using disability adjusted life years (DALYs), with and without discounting and age-weighting. The impact of long-term disabilities on the rHAT burden was also investigated.

Sixty four cases were identified in the study. The majority were identified in second stage, and the mortality rate was high (12.5%). The total number of DALYs was 285 without discounting or age-weighting. When long-term disabilities were included this estimate increased by 50% to 462. The proportion of years lived with disability (YLD) increased from 6.4% to 37% of the undiscounted and un-age-weighted DALY total. When a more active surveillance method was applied in 2013-2014 the cases identified increased dramatically, suggesting a high level of under-reporting. Similarly, the proportion of females increased substantially, indicating that passive surveillance may be especially failing this group.An average of 4.9 months of productive time was lost per patient as a consequence of infection. The health consequences included pain, amnesia and physical disability. The social consequences included stigma, dropping out of education, loss of friends and self-esteem. Results obtained from focus group discussions revealed misconceptions among community members which could be attributed to lack of knowledge about rHAT.

The social and economic impact of rHAT on rural households and communities is substantial. Improved surveillance and strengthening of local medical services are needed for early and accurate diagnosis. Disease prevention should be prioritised in communities at risk of rHAT, and interventions put in place to prevent zoonotic disease spill over from domestic animals and wildlife. Supportive measures to mitigate the long-term effects of disability due to rHAT are needed.

Intestinal schistosomiasis caused by Schistosoma mansoni is a wide spread disease in most parts of Ethiopian highlands. Snail control is one major strategy in schistosomiasis control. The use of molluscicidal plant products is becoming interesting due to their environmental friendliness, accessibility and easy application. This research is aimed to evaluate the molluscicidal effect of Achyranthes aspera on Biomphalaria pfeifferi and Lymnaea natalensis snails, which are of great medical and veterinary importance in Ethiopia.

Adult B. pfeifferi snails were exposed to the various concentrations of A. aspera aqueous leaf extract for 24, 48 and 72 h. Similarly, adult L. natalensis snails were exposed to the extract for 24 h. Mortality data were analyzed using probit regression model. Phytochemical content of the plant was analyzed using standard screening methods.

The plant's molluscicidal effect on the two snail species was demonstrated. The 24 h LC₅₀ and LC₉₀ values against L. natalensis were 69.5 and 93.9 ppm respectively. In the 24, 48 and 72 h exposure of B. pfeifferi, the LC₅₀ values were 72.4, 69.9, 64.7 ppm and the LC₉₀ were 96.5, 93.8, 92.8 ppm, respectively. The phytochemical screening tests indicated presence of saponins.

From the findings of this study, A. aspera has a molluscicidal potential. The result provides a useful foundation for further in-depth studies to ensure its wider applicability in different water bodies and evaluate its toxic effects on non-target species.

The transmission of infectious diseases is a dynamic process determined by multiple factors originating from disease pathogens and/or parasites, vector species, and human populations. These factors interact with each other and demonstrate the intrinsic mechanisms of the disease transmission temporally, spatially, and socially. In this article, we provide a comprehensive perspective, named as systems thinking, for investigating disease dynamics and associated impact factors, by means of emphasizing the entirety of a system's components and the complexity of their interrelated behaviors. We further develop the general steps for performing systems approach to tackling infectious diseases in the real-world settings, so as to expand our abilities to understand, predict, and mitigate infectious diseases.

Interventions are currently being used against 'infectious diseases of poverty', which remain highly debilitating and deadly in most endemic countries, especially malaria, schistosomiasis, echinococcosis and African sleeping sickness. However, major limitations of current 'traditional' methods for diagnosis are neither simple nor convenient for population surveillance, and showed low sensitivity and specificity. Access to novel technologies for the development of adequate and reliable tools are expressly needed. A collaborative project between African Network for Drugs and Diagnostics Innovation and partner institutions in Africa and China aims to screen suitable serological biomarkers for diagnostic pipelines against these 'diseases of the poor'.

Parasite-specific exposed versus unexposed individuals were screened and sera or urine/stools were collected through case-control studies in China and African countries. Target genes/open reading frames were selected, then will be cloned and cell-free expressed, quantified and immuno-detected. Target antigens/epitopes will be probed and screened with sera from exposed or unexposed individuals using a high-throughput antigen screening platform as the study progresses. The specificity and sensitivity of highly immunoreactive biomarkers will be evaluated as well, using enzyme-linked immunosorbent assays or dipsticks.

This roadmap explicitly unfolds the integrated operating procedures with focus on malaria and schistosomiasis, for the identification of suitable biomarkers that will aid the prioritization of diagnostics for population use. However, there is need to further validate any new diagnostic through comparison with standard methods in field deployable tests for each region. Our expectations for the future are to seek regulatory approval and promote the use of diagnostics in endemic areas.

Over the past six decades, the Chinese government made parasitoses with a high disease burden, including soiltransmitted nematode infections, malaria, leishmaniasis, filariasis, and schistosomiasis, a public health priority because they were seen to be crucial impediments to the development of rural areas. As a result, these debilitating parasitic diseases that used to be widely prevalent have been well controlled or eliminated. Consequently, less attention has been paid to parasitic infection during the rapid development of the economy, especially in developed areas. However, our investigations conducted in the parasitological laboratory of Sun Yat-sen University (Guangzhou, Guangdong, China) show that emerging parasitic diseases still threaten many people's health, with 340 of 880 outpatients (38.6%) receiving a diagnosis of parasitic disease, among whom 201 (59.1%) had clonorchiasis and 120 (35.3%) had taeniasis/cysticercosis. Furthermore, our doctors are not equipped with sufficient parasitology knowledge because this discipline is not able to maintain attraction. Many parasitic infections that result in severe consequences are treatable and preventable, but the phenomena of misdiagnosis and missed diagnosis are common and merit attention.

Anopheles sinensis (Diptera: Culicidae) is a primary vector of Plasmodium vivax and Brugia malayi in most regions of China. In addition, its phylogenetic relationship with the cryptic species of the Hyrcanus Group is complex and remains unresolved. Mitochondrial genome sequences are widely used as molecular markers for phylogenetic studies of mosquito species complexes, of which mitochondrial genome data of An. sinensis is not available.

An. sinensis samples was collected from Shandong, China, and identified by molecular marker. Genomic DNA was extracted, followed by the lllumina sequencing. Two complete mitochondrial genomes were assembled and annotated using the mitochondrial genome of An. gambiae as reference. The mitochondrial genomes sequences of the 28 known Anopheles species were aligned and reconstructed phylogenetic tree by Maximum Likelihood (ML) method.

The length of complete mitochondrial genomes of An. sinensis was 15,076 bp and 15,138 bp, consisting of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and an AT-rich control region. As in other insects, most mitochondrial genes are encoded on the J strand, except for ND5, ND4, ND4L, ND1, two rRNA and eight tRNA genes, which are encoded on the N strand. The bootstrap value was set as 1000 in ML analyses. The topologies restored phylogenetic affinity within subfamily Anophelinae. The ML tree showed four major clades, corresponding to the subgenera Cellia, Anopheles, Nyssorhynchus and Kerteszia of the genus Anopheles.

The complete mitochondrial genomes of An. sinensis were obtained. The number, order and transcription direction of An. sinensis mitochondrial genes were the same as in other species of family Culicidae.

Our paper draws attention to recently published HIV and AIDS surveillance data, and shows the failure of the system. While sounding the alarm based on three newly detected PWID HIV cases in the past 2years may be premature, there are definitely serious problems in the HIV detection and tracing system among PWIDs in Hungary.

The case that we discuss in this paper is a male PWID, who was diagnosed with HIV and AIDS in May of 2015 and then died of AIDS the next month. His HIV infection status was detected with delay, and then appeared in the official statistics as an incident PWID HIV case and an incident PWID AIDS case, but not as an incident PWID AIDS death. No contact tracing followed, even though it would have been relatively easy considering the circumstances. To our knowledge, no HIV post-exposure protocol exists in hospitals, in case of HIV exposure due to an eventual needle-stick injury.

Before 2014 (the year of closure of the two largest needle exchange programs in Hungary, which halved the number of available syringes in the country despite increased injecting risk practices) no HIV was reportedly acquired in Hungary among people who inject drugs (PWIDs) who were not also men who had sex with other men (MSM). In 2014, one and in 2015 two non-MSM PWIDs were newly diagnosed with HIV who supposedly became infected in Hungary, and both incident HIV cases in 2015 were diagnosed in the AIDS stage. In addition, two new (albeit supposedly imported) non-MSM PWID cases were also registered in the first three quarters of 2016, one of which subsequently was diagnosed with and then died of AIDS. At the same time, the prevalence of HCV doubled among PWIDs (from 24% to 49% in Hungary and from 34% to 61% in Budapest).