The widespread occurrence of anti-malarial drug resistance threatens the current efforts to control malaria in African regions. Molecular marker surveillance helps to track the emergence and spread of drug-resistant malaria cases.
A total of 237 Plasmodium falciparum infections imported from central Africa to Zhejiang Province, China, between 2016 and 2021, were investigated. Genomic DNA was extracted from blood samples of each patient and nested PCRs was used to detect molecular markers in k13, Pfcrt, and Pfmdr1 genes. The spatial and temporal distributions of the molecular markers were analyzed.
A limited polymorphism of k13 was observed, including two nonsynonymous (D464E and K503E) and five synonymous mutations. Wild-type CVMNK of Pfcrt predominated (78.5%), whereas 19.5% of the samples harbored the mutant haplotype, CVIET. The point mutation Y184F and the single mutant haplotype NF of Pfmdr1 were the most frequently observed. The geographical distributions of the Pfcrt and Pfmdr1 haplotypes displayed distinct patterns, with the mutant haplotype of Pfcrt more common in Gabon (53.9%) and Congo (50.0%), and wild haplotypes of Pfmdr1 more frequently found in Cameroon, Angola, and Congo. The prevalence of wild-type CVMNK of Pfcrt increased from 68.5-74.6% in 2016-2017 to 81.8-87.5% in 2018-2021. The proportion of wild-type Pfmdr1 also increased from 27.1% in 2016 to 38.5% in 2019.
The geographical and temporal distribution of k13, Pfcrt, and Pfmdr1 polymorphisms in P. falciparum parasites imported from central Africa between 2016 and 2021 are demonstrated. Our data provide updated evidence that can be used to adjust anti-malarial drug policies in central Africa and China.

Spatial redistribution of nutrients by atmospheric transport and deposition could theoretically act as a continental-scale mechanism which counteracts declines in soil fertility caused by nutrient lock-up in accumulating biomass in tropical forests in Central Africa. However, to what extent it affects carbon sinks in forests remains elusive. Here we use a terrestrial biosphere model to quantify the impact of changes in atmospheric nitrogen and phosphorus deposition on plant nutrition and biomass carbon sink at a typical lowland forest site in Central Africa. We find that the increase in nutrient deposition since the 1980s could have contributed to the carbon sink over the past four decades up to an extent which is similar to that from the combined effects of increasing atmospheric carbon dioxide and climate change. Furthermore, we find that the modelled carbon sink responds to changes in phosphorus deposition, but less so to nitrogen deposition. The pronounced response of ecosystem productivity to changes in nutrient deposition illustrates a potential mechanism that could control carbon sinks in Central Africa. Monitoring the quantity and quality of nutrient deposition is needed in this region, given the changes in nutrient deposition due to human land use.

Sulfadoxine-pyrimethamine (SP) resistance impairs the efficacy of antimalarial drugs. Monitoring molecular markers in exported malaria infections provides an efficient way to trace the emergence of drug resistance in countries where malaria is endemic. Molecular markers in Pfdhfr and Pfdhps of 237 Plasmodium falciparum infections imported from central Africa between 2016 and 2021 were detected. The spatial and temporal distributions of Pfdhfr and Pfdhps mutations were analyzed. A high prevalence of Pfdhfr single-nucleotide polymorphisms (SNPs) (~92.34% to 99.10%) and a high frequency of the triple mutation haplotype I51R59N108 were observed. Cameroon, Equatorial Guinea, and Gabon showed a higher frequency (~96.61% to 100.00%) of I51R59N108 than other countries (~71.11% to 88.10%). The prevalence of C59R and I51R59N108 increased while that of other SNPs or haplotypes did not fluctuate greatly from 2016 to 2021. Large proportions of Pfdhps SNPs (A437G and K540E) were demonstrated. The SNP distribution of Pfdhps differed between countries, with S436A dominating in northern countries and A437G dominating in others. The proportions of I431V, A437G, and the triple mutant haplotype declined between 2016 and 2021, whereas the prevalence of the single mutant haplotype rose from 61.60% to 73.68%. Combinations of Pfdhfr-Pfdhps alleles conferring partial resistance, full resistance, and superresistance to SP, as defined in the text, were detected in 63.64%, 8.64%, and 0.91% of the samples, respectively. The octuple Pfdhfr-Pfdhps allele (I51R59N108-V431A436G437K540G581S613) was seen in 5.00% of the samples. We demonstrated the wide geographic spread and increasing trends in highly SP-resistant Pfdhfr genes and varying spatial patterns of Pfdhps mutants across countries in central Africa. The high prevalences of partially resistant, fully resistant, and superresistant Pfdhfr-Pfdhps combinations observed here indicated impaired SP efficacy. Increased molecular surveillance is required to monitor the changing status of the Pfdhfr and Pfdhps genes. IMPORTANCE Monitoring drug resistance is important for malaria control because its early detection enables timely action to prevent its spread and mitigate its impact. The wide geographic spread and the increasing trend of highly resistant Pfdhfr genes between 2016 and 2021 found in our study are worrisome and emphasize the urgency to monitor their updated status in central Africa. This study also illustrated the wide spread of the novel mutant Pfdhps I431V as well as the high prevalence of \"partially resistant,\" \"fully resistant,\" and \"superresistant\" Pfdhfr-Pfdhps combinations, indicating the urgent concern for SP efficacy in central Africa. These findings are alarming in central African countries where malaria is endemic, where SP was is widely used for the intermittent preventive treatment of malaria in pregnancy (IPTp) and the intermittent preventive treatment of malaria in infants below 5 years of age (IPTi), and urge enhanced molecular surveillance and responses to the threat of drug resistance.

Yellow fever (YF) is a major public-health problem in Africa. Yellow fever virus (YFV), the etiological agent responsible for the disease, exhibits clear delineation of phylogeography between East/Central Africa and West Africa. In order to decipher the genetic nature of the YFV epidemic between these areas, we performed a genome-wide study on its African isolates using the McDonald-Kreitman (MK) test in combination with the type II functional divergence analysis. The results showed that adaptive genetic diversifications have occurred on viral nonstructural protein 1 (NS1) and NS5, which are essential for viral genome replication and immune antagonism, with the East/Central African-West African epidemic split. On both proteins, a number of amino acid replacements have been favored by functional divergence. These findings could help to bridge the gap between the phylogeographic delineation and niche adaptation underlying the YFV-epidemic across Africa and shed light on viral determinants of this process.

Tuberculosis (TB) incidence and mortality rates are still high in Sub-Saharan Africa, and the knowledge about the current patterns is valuable for policymaking to decrease the TB burden. Based on the Global Burden of Disease (GBD) study 2019, we used a Joinpoint regression analysis to examine the variations in the trends of TB incidence and mortality, and the age-period-cohort statistical model to evaluate their risks associated with age, period, and cohort in males and females from Cameroon (CAM), Central African Republic (CAR), Chad, and the Democratic Republic of the Congo (DRC). In the four countries, TB incidence and mortality rates displayed decreasing trends in men and women; except for the males from DRC that recorded an almost steady pattern in the trend of TB incidence between 1990 and 2019. TB incidence and mortality rates decreased according to the overall annual percentage changes over the adjusted age category in men and women of the four countries, and CAM registered the highest decrease. Although TB incidence and mortality rates increased with age between 1990 and 2019, the male gender was mainly associated with the upward behaviors of TB incidence rates, and the female gender association was with the upward behaviors of TB mortality rates. Males and females aged between 15-54 and 15-49 years old were evaluated as the population at high risks of TB incidence and mortality respectively in CAM, CAR, Chad, and DRC. The period and cohort relative risks (RRs) both declined in men and women of the four countries although there were some upward behaviors in their trends. Relatively to the period and cohort RRs, females and males from CAM recorded the most significant decrease compared to the rest of the countries. New public health approaches and policies towards young adults and adults, and a particular focus on elderlies\' health and life conditions should be adopted in CAM, CAR, DRC, and Chad to rapidly decrease TB incidence and mortality in both genders of the four countries.

As the biodiversity crisis continues, we must redouble efforts to understand and curb pressures pushing species closer to extinction. One major driver is the unsustainable trade of wildlife. Trade in internationally regulated species gains the most research attention, but this only accounts for a minority of traded species and we risk failing to appreciate the scale and impacts of unregulated legal trade. Despite being legal, trade puts pressure on wild species via direct collection, introduced pathogens, and invasive species. Smaller species-rich vertebrates, such as reptiles, fish, and amphibians, may be particularly vulnerable to trading because of gaps in regulations, small distributions, and demand of novel species. Here, we combine data from five sources: online web searches in six languages, Convention on International Trade in Endangered Species (CITES) trade database, Law Enforcement Management Information System (LEMIS) trade inventory, IUCN assessments, and a recent literature review, to characterise the global trade in amphibians, and also map use by purpose including meat, pets, medicinal, and for research. We show that 1215 species are being traded (17% of amphibian species), almost three times previous recorded numbers, 345 are threatened, and 100 Data Deficient or unassessed. Traded species origin hotspots include South America, China, and Central Africa; sources indicate 42% of amphibians are taken from the wild. Newly described species can be rapidly traded (mean time lag of 6.5 years), including threatened and unassessed species. The scale and limited regulation of the amphibian trade, paired with the triptych of connected pressures (collection, pathogens, invasive species), warrants a re-examination of the wildlife trade status quo, application of the precautionary principle in regard to wildlife trade, and a renewed push to achieve global biodiversity goals.
In the last few decades, exotic pets have become much more common. In the UK in 2008, reptiles and amphibians were more popular than dogs, with over eight million in captivity. But while almost all pet cats and dogs are born and bred in captivity, exotic pets are often taken from the wild, putting species and their habitats at risk. An international trade agreement called the Convention on International Trade in Endangered Species (CITES) strives to prevent unsustainable animal trade. But to get CITES protection, species depend on data showing that wildlife trade threatens their survival. In addition, their range countries need to first propose them to be listed. For most wild animal species, there are no data on population size or population decline. In the case of amphibians, CITES regulates the trade of just 2.5% of species. This leaves the rest with no protection from overarching international trade regulations. To protect these animals, researchers need to find out which species are in trade, where they are coming from, and how many are already threatened. To address this, Hughes, Marshall and Strine combined data from five sources, including official CITES trade records, recent research and an online search for amphibian sales in six languages. The data showed evidence of trade in at least 1,215 amphibian species, representing 17% of all amphibians. The figure is three times higher than previous estimates. Of the species in trade, more than one in five is vulnerable to extinction, endangered, or critically endangered. For a further 100 of the traded species, data on population were unavailable. Moreover, analysis of the origins of traded individuals showed that around 42% came from the wild. Tropical parts of the world had the highest number of species in trade, but the data showed exchanges happening across the globe. Unsustainable wildlife trade can have devastating consequences for wild animals. It has already driven at least 21 reptile species to extinction, and data of amphibian species are unknown. To prevent further species going extinct, legal wildlife trade should follow the precautionary principle when it comes to wildlife trade. Rather than allowing people to trade a species until CITES regulates it, a blanket ban should come into force for species that have not been assessed or are threatened. Trade would be able to resume for a species only when assessments show that it would not cause major population decline, or secure, captive breeding facilities can be guaranteed.

BACKGROUND: Travel-related malaria in non-endemic areas returning from endemic areas presents important challenges to diagnosis and treatment. Imported malaria to newly malaria-free countries poses further threats of malaria re-introduction and potential resurgence. For those traveling to places with high Plasmodium falciparum prevalence, prophylaxis against this parasite is recommended, whereas causal prophylaxis against relapsing malaria is often overlooked.
METHODS: We analyzed a cluster of imported malaria among febrile patients in Shanglin County, Guangxi Province, China, who had recent travel histories to Western and Central Africa. Malaria was diagnosed by microscopy and subsequently confirmed by species- and subspecies-specific PCR. Plasmodium vivax was genotyped using a barcode consisting of 42 single nucleotide polymorphisms.
RESULTS: Investigations of 344 PCR-confirmed malaria cases revealed that in addition to Plasmodium falciparum being the major parasite species, the relapsing parasites Plasmodium ovale and P. vivax accounted for ~40% of these imported cases. Of the 114 P. ovale infections, 65.8% and 34.2% were P. ovale curtisi and P. ovale wallikeri, respectively, with the two subspecies having a ~2:1 ratio in both Western and Central Africa. Phylogenetic analysis of 14 P. vivax isolates using a genetic barcode demonstrated that 11 formed a distinct clade from P. vivax populations from Eastern Africa.
CONCLUSIONS: This study provides support for active P. vivax transmission in areas with the predominant Duffy-negative blood group. With relapsing malaria making a substantial proportion of the imported malaria, causal prophylaxis should be advocated to travelers with a travel destination to Western and Central Africa.

Imported cases of infectious disease provide invaluable information about epidemiological conditions abroad, and should guide treatment decisions at home and abroad. Here, we examined cases of malaria imported from Africa to China for mutations eroding the efficacy of sulfadoxine-pyrimethamine (SP), sometimes used as an intermittent preventive treatment during for pregnant women and infants.
A total of 208 blood samples were collected from P. falciparum-infected workers who had returned from Western and Central Africa to Guangxi Province Frequency distribution. Samples were analyzed for the mutations in dhfr and dhps genes by PCR -sequencing. The prevalence of dhfr and dhps polymorphisms was analyzed. Among the isolates, polymorphisms were detected in mutants N51I, C59R, S108N and I164L of Pfdhfr and I431V, S436 A/F, A437G, K540 E/N, A581G and A613T of pfdhps.
Mutations promoting drug resistance were widespread in this cohort. For pfdhfr and pfdhps, wild types were equally rare among patients returned from Western Africa and Central Africa. A triple-mutant dhfr haplotype was most prevalent (>70%). We report for the first time mutation I164L-dhfr and I431V-dhps in Ghana, and for the first time we found A581G to exceed a clinically-relevant threshold that may counter-indicate current clinical practices. For Pfdhps, the double-mutant IAGKAA was high prevalent haplotype in Ghana, Western Africa. The single-mutant ISGKAA was a majority haplotype in Cameroon. Alarmingly, a \"super resistance\" quintuple mutant was detected, for the first time, in parasites of West African origin (defined by IAGKAA/IRNI in combination with pfdhps 581G and dhfr I164L). This may limit the efficacy of this drug combination for even intermittent clinical applications.
These data are cause for great concern and call for continued surveillance of the efficacy of SP in source and recipient populations, and should be considered when developing treatment policy for imported malaria cases in China and elsewhere.

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A licensed vaccine against Ebola virus (EBOV) remains unavailable, despite >11 000 deaths from the 2014-2016 outbreak of EBOV disease in West Africa. Past studies have shown that recombinant vaccine viruses expressing EBOV glycoprotein (GP) are able to protect nonhuman primates (NHPs) from a lethal EBOV challenge. However, these vaccines express the viral GP-based EBOV variants found in Central Africa, which has 97.3% amino acid homology to the Makona variant found in West Africa. Our previous study showed that a recombinant adenovirus serotype 5 (Ad5)-vectored vaccine expressing the Makona EBOV GP (MakGP) was safe and immunogenic during clinical trials in China, but it is unknown whether the vaccine protects against EBOV infection. Here, we demonstrate that guinea pigs immunized with Ad5-MakGP developed robust humoral responses and were protected against exposure to guinea pig-adapted EBOV. Ad5-MakGP also elicited specific B- and T-cell immunity in NHPs and conferred 100% protection when animals were challenged 4 weeks after immunization. These results support further clinical development of this candidate and highlight the utility of Ad5-MakGP as a prophylactic measure in future outbreaks of EBOV disease.