Hepatitis B infection is associated with asymptomatic malaria in the Brazilian Amazon

Background

Areas that are endemic for malaria are also highly endemic for hepatitis B virus (HBV) infection. Nevertheless, it is unknown whether HBV infection modifies the clinical presentation of malaria. This study aimed to address this question.

Methodology and Findings

An observational study of 636 individuals was performed in Rondônia, western Amazon, Brazil between 2006 and 2007. Active and passive case detections identified Plasmodium infection by field microscopy and nested Polymerase Chain Reaction (PCR). HBV infections were identified by serology and confirmed by real-time PCR. Epidemiological information and plasma cytokine profiles were studied. The data were analyzed using adjusted multinomial logistic regression. Plasmodium-infected individuals with active HBV infection were more likely to be asymptomatic (OR: 120.13, P<0.0001), present with lower levels of parasitemia and demonstrate a decreased inflammatory cytokine profile. Nevertheless, co-infected individuals presented higher HBV viremia. Plasmodium parasitemia inversely correlated with plasma HBV DNA levels (r = −0.6; P = 0.0003).

Conclusion

HBV infection diminishes the intensity of malaria infection in individuals from this endemic area. This effect seems related to cytokine balance and control of inflammatory responses. These findings add important insights to the understanding of the factors affecting the clinical outcomes of malaria in endemic regions.     

Amebic liver abscess: epidemiology, clinical features, and outcome

Amebic liver abscess (ALA) is a serious, but readily treatable form of hepatic infection. In order to understand the clinical features of this condition in the United States, we reviewed the medical histories of 56 patients with ALA at two large San Francisco Hospitals from 1979 to 1994. Patients were divided into the following groups based on the presumed manner in which they had acquired ALA: those born or raised in the United States, with a history of travel to an endemic area (Tr-ALA); those from an endemic area, but living in the United States for less than one year (En-ALA); and those neither from nor having traveled to an endemic area (N-ALA). We found distinct clinical patterns in patients from different epidemiological groups. Patients with Tr-ALA were a decade older than those from endemic regions, were more likely to be male, and tended to have an insidious onset. Furthermore, compared to patients with En-ALA, those with Tr-ALA were more likely to have hepatomegaly (P < 0.0001) and large abscesses (ALA > 10 cm; P < 0.01). One third of the patients studied had no associated travel history or endemic origin as risk factors. Of these, 63% had a condition consistent with severe immunosuppression, such as infection with the human immunodeficiency virus (HIV), malnourishment with severe hypoalbuminemia, or chronic infection. In patients with N-ALA, the presence of a presumed immunosuppressed state increased significantly, as compared to patients with endemic or travel risk factors for ALA. During the last five years of the study, one third of all patients diagnosed with ALA were HIV positive (including 2 with a new diagnosis of AIDS), many of whom were discovered to be HIV-infected only after presentation with ALA. We conclude that travel to and origin in an endemic area are important risk factors for the development of ALA, and patients in these different epidemiological groups appear to have distinct clinical features. Further, in the absence of recognized risk factors, the development of ALA may suggest an immunocompromised host.     

Leishmania (Leishmania) infantum/chagasi: Histopathological aspects of the skin in naturally infected dogs in two endemic areas

In the New World, visceral leishmaniasis (VL), which is a progressive disease and frequently fatal, is caused by Leishmania (Leishmania) infantum/chagasi. It is endemic in many regions of Brazil and occasionally occurs in non-endemic regions when dogs from an endemic area are introduced. The aim of the present study is to compare different skin infection patterns of dogs from two leishmaniasis endemic areas. A histological analysis of dogs from Campo Grande, Mato Grosso do Sul state, a region where epidemic episodes are currently taking place, showed dermic inflammatory infiltrates, composed of numerous vacuolated parasitized macrophages, few lymphocytes, plasma cells and many degranulated mast cells. In the other region of the study, São Luís, Maranhão state, the skin of dogs presented a remarkable inflammatory reaction composed mainly of plasma cells, lymphocytes and very few parasites. We concluded that there is a difference in the skin lesion patterns of dogs with leishmaniasis that is directly related to the endemic area where the animals live.     

High prevalence of Fasciolopsis buski in an endemic area of liver fluke infection in Thailand

There is a high prevalence of Fasciolopsis buski in Sawasdee Village in the Nam Som District, Udonthani Province in northeastern Thailand, an endemic area of liver fluke infection. From stool examination of 183 villagers participating in the study, the authors detected a fluke parasitic infection rate of 14.8% (27 cases). Of interest, the authors found a similar high prevalence of both Opisthorchis viverrini (16 cases, 8.7%) and F buski (13 cases, 7.1%). This region is the endemic area of liver fluke, not of F buski. The surrounding environment is the hill area of Nayoong Namsom mountain, which is not a suitable area for F buski larvae. However, the village has been inhabited by a number of immigrants from various regions of Thailand over the past few years. The F buski can be carried by these people, possibly explaining the migration of the fluke parasite to this setting. The nonendemic parasite infection was also detected at high prevalence in the community. Wide spectrum control for various parasitic infections in villages like Sawasdee is necessary.     

四川分布的中国种子植物特有科属研究

对传统“特有”概念作了补充说明,确认四川有中国种子植物特有类群129属,12个特有科,在国产特有类群中占有较大比例。生活型虽然以草本为主,但高比例（近1／3）的木本类型以及木本类型多为原始的古特有成分却反映出植物区系的古老性和悠久发展历史。地理分布以盆地四周山地最丰富,西部高原和盆地中部缺乏或少有特有科、属。总体上可划分为3个分布中心区,包括西南区、东南区和东北区。新特有成分以西南区较多,而古特有成分大多集中中东南区和东北区。特有属与邻近地区的相似性还反映了四川植物区系和邻近地区植物区系的整体性。丰富的特有科、属同时也反映出四川种子植物区系的多样性。     

Host--parasite relationships of Schistosoma japonicum in mammalian hosts.

Control of schistosomiasis caused by Schistosoma japonicum has been severely hindered by the fact that several non-human mammalian species, including domesticated as well as wild animals, serve as zoonotic carriers of this infection. For effective control, it is imperative that the full host spectrum of this infection is understood. Although about 46 species of mammals are known to carry natural infection with S. japonicum, only a few might be of potential threat to human infection. Generally, in an endemic area, transmission of schistosomiasis to human depends largely on the availability and abundance of permissive hosts. Another important factor that needs to be taken into consideration in developing control measures against S. japonicum is potential strain differences. This review collates pertinent host-parasite relationship of S. japonicum in mammals in an endemic area and assesses the epidemiological significance of these findings for human infection.     

Strongyloidiasis associated with human T-cell lymphotropic virus type I infection in a nonendemic area.

Concomitant strongyloidiasis and human T-cell lymphotropic virus type I (HTLV-I) infection has been reported from areas in Japan where both organisms are endemic. We present four cases of concomitant infection with these organisms from an area that is not endemic for Strongyloides stercoralis. Three of the four patients had adult T-cell leukemia, an aggressive neoplasm resulting from HTLV-I infection, while the other was an asymptomatic carrier of HTLV-I. Three of the patients had spent their childhoods in an endemic location for both organisms, suggesting an initial infection at that time. Three patients were symptomatic from their parasitism. We conclude that strongyloidiasis may be found in nonendemic locations in patients with either adult T-cell leukemia or an asymptomatic HTLV-I carrier state. Whether infestation with this parasite contributes to the leukemogenesis of HTLV-I, as postulated by others, cannot at this time be determined.     

Risk factors for Trypanosoma cruzi infection among blood donors in central Brazil.

Characteristics and possible risk factors associated with Trypanosoma cruzi infection among blood donors were assessed within a routine screening programme in blood banks in an endemic area of Chagas disease. 6,172 voluntary blood donors were interviewed and tested for anti-T. cruzi antibodies by Haemagglutination and Complement Fixation tests in six blood banks in Goiania-Central Brazil from October 1988 to April 1989. An overall prevalence of 2.3% for T. cruzi infection was obtained, being 3.3% for first-time blood donors and 1.9% for regular ones (p < 0.01). Considering this seropositivity among regular blood donors, selection of candidates relying only on the history of previous donation was found to be inadequate. The risk of infection increased inversely with the degrees of education and monthly income. There was a 9.2 risk of infection (95% CI 3.8-22.6) for those who had lived more than 21 years in an endemic area compared to subjects who had never lived in rural settings, after multivariate analysis. These informations may help to review the criteria of selection of donors in order to improve quality of blood products in endemic areas.     

Gymnophalloides seoi eggs from the stool of a 17th century female mummy found in Hadong, Republic of Korea

It was previously reported that paleoparasitological clues for parasites infecting humans could be found in the feces of mummies of the Joseon Dynasty (1392-1910) in the Republic of Korea. Here, we report the presence of trematode eggs, including Clonorchis sinensis, Metagonimus yokogawai, and Gymnophalloides seoi (a human parasite known in Korea since 1993) in the feces of a recently excavated female mummy in Hadong, Republic of Korea. This is the first report of the discovery of a G. seoi infection in a human mummy. Since Hadong is currently not an endemic area for G. seoi, we speculate that the parasite might have occurred frequently along coastal areas of the Korean peninsula several hundred years ago and that the endemic areas contracted to, more or less, restricted regions since that time.     

华中地区藤本种子植物区系的研究

以湖南和湖北两省为代表对华中地区藤本种子植物的区系进行了研究。本区共有藤本种子植物62科175属838种,其中土著种类有60科159属784种。在科、属、种的水平上对藤本种子植物区系特性进行了较深入的统计和分析,并对本区藤本种子植物与邻近地区的关系、本区内的藤本种子植物的地带性分异进行了探讨。统计表明,本区藤本种子植物种数占该区种子植物总种数的11%,且61.7%的种类主要集中在30种以上的大科中;热带分布型明显多于温带分布型;泛热带、热带亚洲、东亚（中国）特有和东亚—北美间断分布科属比较集中,其中许多属为古老成分;本区藤本种子植物特有成分丰富,计有东亚特有科1科、中国特有属6属、中国特有种507种（其中华中地区特有种35种）。通过研究认为：本区藤本种子植物具有种类丰富、分布类型多样、特有成分较多、区系较古老的特点;与本区的全部种子植物区系相比,藤本种子植物区系的热带性更强,具有明显的热带亲缘性,并与喜马拉雅及中国西南有较强的地理渊源。     

海南竹类的地理分布及区系特征

通过对海南岛竹类区系地理成分进行统计、分析和对其分布、与邻近地区竹类区系关系的探讨,其区系特征归纳如下:1.拥有丰富的特有成分。2.区系的热带性质明显。3.分布上差异显著。4.区系原始、古老。5.与毗邻的广东竹类区系联系较多。     

Species diversity,endemism and conservation of the family Caryophyllaceae in Greece

The family Caryophyllaceae includes world-wide 86 genera and approximately 2100 species. Greece is one of its most important centres of diversity and endemism. A total of 428 Caryophyllaceae taxa are distributed in Greece, 161 of them being endemic to the Greek political territory. The endemic element represents approximately 5% of the global diversity of the family at the species level. The aim of this paper is to discuss the distribution patterns of the Greek endemic Caryophyllaceae, as well as those with a limited distribution range to the neighbouring areas of the Balkans and Anatolia, on the basis of the phytogeographical regions of Greece in order to identify the important regions for their conservation. The majority of the Greek endemic Caryophyllaceae (64.6%) are distributed in only one single phytogeographical region, or even a smaller area indicating the extremely restricted distribution ranges of the endemic plants in Greece. Actually 83 Greek endemic Caryophyllaceae can be grouped on cytotaxonomic criteria. Most of them belong to the category of schizoendemics (91.6%), indicating that the endemism of Caryophyllaceae in Greece has mainly originated in an active way. Cluster analysis has been used to classify the phytogeographical regions according to their floristic similarities. Two iterative complementarity methods were used to evaluate the importance of each phytogeographical region in the conservation of the endemic Caryophyllaceae in Greece. Peloponnisos, Kriti-Karpathos and Sterea Ellas are the most important phytogeographical regions in this respect, followed by North Central and North East. When adding the Balkan-Aegean-Anatolian endemics to the analysis, Peloponnisos, North Central, Kriti-Karpathos, North East and Eastern Aegean result as the most important areas. In every case, an elevated number of sites are required for the conservation of Caryophyllaceae in Greece, reflecting the great dissimilarities in the floristic composition of the various phytogeographical regions. The results provided by the different methods are compared. A catalogue of the Greek endemic Caryophyllaceae is appended.     

滇中小百草岭多变石栎林植物区系的初步研究

多变石栎林是小百草岭地区亚热带山地植被垂直带上最具特征性的植被类型 ,也是该地区州级自然保护区境内面积最大、保存最为完整、最有保护价值的植被类型。通过该植被类型中 116种常见种和优势种的群落结构和植物区系分析表明 :仅有中国特有分布种和中国-喜马拉雅分布种能贯穿于该植被类型的整个群落结构之中 ,植物区系成分以热带亚洲、中国 -喜马拉雅和中国特有类型为主 ,表明它隶属东亚植物区 ,中国 -喜马拉雅森林植物亚区 ,云南高原地区 ,云南高原亚地区 (IIIE13a)的一个具体区系单元的基本特征 ;其中的中国特有种又以小百草岭与周边的滇西北、川、黔、藏地区 (主要为横断山地区 )所共有的种占优势 ,从而也表明了小百草岭种子植物区系与横断山植物区系的联系相对紧密 ;通过与周边地区相同植被类型的比较 ,显示其地处滇中高原北缘的地理位置及受金沙江干热河谷气候影响使得该植被类型垂直分布海拔较高 ,更偏“干”的特点。     

High prevalence of Opisthorchis viverrini infection in reservoir hosts in four districts of Khon Kaen Province, an opisthorchiasis endemic area of Thailand

Khon Kaen, a northeastern province of Thailand, has been considered as one of the human opisthorchiasis endemic areas with continuing high prevalence. Unsuccessful eradication of the disease is probably from the culture of eating raw and undercooked fish of local residence and the parasitic persistency in animal reservoir hosts, such as cats and dogs. In cooperation with the other human opisthorchiasis control programs in an endemic area of 29 villages in Ban Haet, Ban Phai, Chonnabot and Muncha Khiri Districts, Khon Kaen, this study investigated the prevalence of Opisthorchis viverrini infection using a formalin-ether sedimentation method as the gold standard, and hematology and blood chemistry of the reservoir hosts in this endemic area. The results showed that cats had much higher prevalence (76 of 214, 35.51%) than dogs (3 of 821, 0.37%). Hematology between the infected and uninfected cats was not different. Complete blood count and biochemistry reflected some altered hepatic functions. However, only severely infected cats showed apparent clinical signs, including lethargy, diarrhea, ocular and nasal discharges. Moreover, the ultrasonogram of infected cats with very high egg per gram (> 1500 EPG) showed apparent thickening of the gall bladder wall with hyperechoicity of hepatic parenchyma. This study suggests that cat is the most important animal reservoir of human opisthorchiasis, especially in this endemic area. It is also interesting that villages with infection are mostly located in the vicinity of Chi River and two large water reservoirs (Lawa and Nong Kongkaew Lakes), but people without infection were away from Chi River, on the south of Kudkhow Lake. Further investigation on this particular geofactor is essential for effective opisthorchiasis control programs.     

Patterns of co-association of C-reactive protein and nitric oxide in malaria in endemic areas of Iran

In addition to numerous immune factors, C-reactive protein (CRP) and nitric oxide (NO) are believed to be molecules of malaria immunopathology. The objective of this study was to detect CRP and NO inductions by agglutination latex test and Griess microassay respectively in both control and malaria groups from endemic areas of Iran, including Southeastern (SE) (Sistan & Balouchestan, Hormozgan, Kerman) and Northwestern (NW) provinces (Ardabil). The results indicated that CRP and NO are produced in all malaria endemic areas of Iran. In addition, more CRP and NO positive cases were observed amongst malaria patients in comparison with those in control group. A variable co-association of CRP/NO production were detected between control and malaria groups, which depended upon the malaria endemic areas and the type of plasmodia infection. The percentage of CRP/NO positive cases was observed to be lower in NW compare to SE region, which may be due to the different type of plasmodium in the NW (Plasmodium vivax) with SE area (P. vivax, Plasmodium falciparum, mixed infection). The fluctuations in CRP/NO induction may be consistent with genetic background of patients. Although, CRP/NO may play important role in malaria, their actual function and interaction in clinical forms of disease remains unclear.     

湖南省德夯风景名胜区种子植物区系研究北大核心CSCD

该研究在对德夯风景名胜区种子植物进行多次野外调查及查阅相关资料文献的基础上,从科、属、种层面、不同特殊生境类型,并与邻近地区进行比较,综合分析探讨德夯的植物区系特征,深入揭示该区植物区系的性质和地位,为该区自然资源的保护和管理以及持续利用提供科学依据。结果表明:(1)德夯种子植物类群丰富,该区共有野生种子植物154科710属1 626种,分别占武陵山地区种子植物科、属、种总数的94.48%、83.43%、54.00%,分别占湖南省种子植物科、属、种总数的73.33%、54.20%、33.46%。(2)该区种子植物区系地理成分复杂,科含12个分布区类型,属含14个,种含15个,科和属的地理成分均以泛热带分布型所占比例最高,种的地理成分以中国特有分布型所占比例最高;特有现象明显,该区含7个东亚特有科、2个中国特有科,27个中国特有属,588个中国特有种,其中含39个华中特有种,29个武陵山地区特有种和6个德夯特有种。(3)该区植物区系成分随生境不同出现分化,台地、悬崖、谷地3种代表性生境区系成分差异明显,和邻近的壶瓶山、小溪、乌龙山3个地区具有较高的相似性。总体上,德夯风景名胜区植物区系具有东亚植物区系特征,在武陵山地区植物区系中具有重要地位。     

Host persistence or extinction from emerging infectious disease: insights from white-nose syndrome in endemic and invading regions

Predicting species'' fates following the introduction of a novel pathogen is a significant and growing problem in conservation. Comparing disease dynamics between introduced and endemic regions can offer insight into which naive hosts will persist or go extinct, with disease acting as a filter on host communities. We examined four hypothesized mechanisms for host–pathogen persistence by comparing host infection patterns and environmental reservoirs for Pseudogymnoascus destructans (the causative agent of white-nose syndrome) in Asia, an endemic region, and North America, where the pathogen has recently invaded. Although colony sizes of bats and hibernacula temperatures were very similar, both infection prevalence and fungal loads were much lower on bats and in the environment in Asia than North America. These results indicate that transmission intensity and pathogen growth are lower in Asia, likely due to higher host resistance to pathogen growth in this endemic region, and not due to host tolerance, lower transmission due to smaller populations, or lower environmentally driven pathogen growth rate. Disease filtering also appears to be favouring initially resistant species in North America. More broadly, determining the mechanisms allowing species persistence in endemic regions can help identify species at greater risk of extinction in introduced regions, and determine the consequences for disease dynamics and host–pathogen coevolution.     

Tropical theileriosis in Tunisia: epidemiology and control

In Tunisia, tropical theileriosis (Theileria annulata infection of cattle) is one of the major diseases affecting cattle in the summer. Each year about 2,500 clinical cases are recorded in the country, mainly in pure-bred animals. An attempt was made in the North of Tunisia to estimate the direct cost related to clinical cases of TT. In the endemic regions, three states of endemicity were described according to cattle age categories at highest disease risk: (i) endemic stability, (ii) low endemic instability, (iii) high endemic instability. The characterisation of these endemic situations, which are conditioned by the levels of the vector tick population and the quantitative aspects of the infection in ticks, are highly relevant for the development of a live attenuated cell line vaccine against TT targeting the cattle population at disease risk in Tunisia. A research programme was set up to develop the attenuation of four local parasite stocks. Two cell lines infected with two distinct T. annulata stocks were tested in the field on pure-bred animals of different age groups from regions with high disease incidence. The vaccination with each of the two cell lines showed a high efficacy. However significant differences in vaccine reactions rates were observed between the two attenuated cell lines emphasising the importance of achieving an optimal balance between protection and vaccine tolerance particularly in pure-bred lactating cows.     

Prevalence of cryptosporidiosis among the villagers and domestic animals in several rural areas of Korea

The present study was undertaken to investigate the infection status of Cryptosporidium parvum in the villagers and the reservoir hosts in several rural areas in Korea. A total 5,262 fecal samples were collected from the inhabitants residing at Gangwon-do, Chungcheongbuk-do, Jeollanam-do, and Gyeongsangnam-do between the dates of September, 2001 to June, 2002. In addition, 1,453 fecal samples were collected from livestock reared in Gokseong-gun, Jeollanam-do and Chungju-si, Chungcheongbuk-do. All the fecal smears were prepared by formalin-ether sedimentation, and examined by light microscopy after modified acid-fast staining. The overall positive rate of human cryptosporidiosis was 3.3%. Gokseong-gun, Jeollanam-do showed a 8.2% positive rate and appeared as the highest endemic area among the surveyed areas. Haman-gun, Gyeongsangnam-do showed a 0.4% positive rate and was the lowest endemic area. The positive rate of livestock infection in Gokseong-gun, Jeollanam-do was 94%, which was more than ten times higher than that of Chungju-si, Chungcheongbuk-do (9.3%). From these results, it was revealed that cryptosporidiosis was an endemic disease in some rural areas of Korea, and the livestock could be an important source of human infection.     

Immunologic hypo- or non-responder in natural dengue virus infection

Serologically defined primary dengue virus infection and/or subsequent homologous serotype infection is known to be associated with less severe disease as compared with secondary subsequent heterologous serotype infection. In geographical locales of high dengue endemicity, almost all individuals in the population are infected at some point in time and should therefore are at high risk of secondary infection. Interestingly, dengue viremia in healthy blood donors whose sera apparently lack detectable levels of specific antibody to dengue viral antigens has been reported. The incidence rate of potential immunologic hypo- or non-responders following natural primary dengue virus infection in dengue endemic regions, who do become immune responders only after repeated exposure, has not been described. These are the patients who may be diagnosed as primary infection in the subsequent infection, but actually are secondary infection. This concept has important implications with regards to the hypothesis of immunological enhancement of dengue pathogenesis, which has largely been advanced based on empirical observations and/or from in vitro experimental assays. The fact that dengue naïve travelers can suffer from severe dengue upon primary exposure while visiting dengue endemic countries underscores one of the major problems in explaining the role of immune enhancement in the pathogenesis of severe dengue virus infection. This evidence suggests that the mechanism(s) leading to severe dengue may not be associated with pre-existing enhancing antibody. Consequently, we propose a new paradigm for dengue virus infection classification. These include a) patients with naïve primary infection, b) those that are serologically defined primary in dengue endemic zones and c) those who are serologically defined secondary dengue virus infection. We submit that clarity with regards to such definitions may help facilitate the delineation of the potential mechanisms of severe dengue virus infection.