Faecal contamination of a tropical river in Nigeria and possible health risks

Information on the hygienic status of surface water is a major public health priority in tropical developing countries. The incidence and occurrence of indicator organisms and pathogenic Salmonellae were studied in a tropical river, the Kaduna, Nigeria, affected by urban waste‐water discharges mainly through open surface drains. The results indicate gross faecal contamination of both the urban waste‐water discharges and the receiving river. By using FC:FS ratios to determine the faecal pollution origin, it was evident that both human and animal sources pollute the river. This signifies that both sources of pollution should be considered in setting bacteriological standards for the waste‐water‐receiving surface water. Klebsiella and Escherichia spp. had similar frequencies of occurrence in the river. The urban effluent receiving river also carried Klebsiella pneumonia, Escherichia coli and pathogenic Salmonella spp. It was concluded that the use of urban waste‐water discharges and the receiving river for irrigation, recreation and water supply poses health risks to the public.     

Progress towards hepatitis B prevention through vaccination in the Western Pacific, 1990–2014

Hepatitis B infections are responsible for more than 300 thousand deaths per year in the Western Pacific Region. Because of this high burden, the countries and areas of the Region established a goal of reducing hepatitis B chronic infection prevalence among children to less than 1% by 2017. This study was conducted to measure the progress in hepatitis B prevention and assess the status of achievement of the 2017 Regional hepatitis B control goal. A literature review was conducted to identify studies of hepatitis B prevalence in the countries and areas of the region, both before and after vaccine introduction. A mathematical model was applied to assess infections and deaths prevented by hepatitis B vaccination and hepatitis B prevalence in countries without recent empirical data. The majority of countries and areas (22 out of 36) were estimated to have over 8% prevalence of chronic hepatitis B infection among persons born before vaccine introduction. After introduction of hepatitis B vaccine, most countries and areas (24 out of 36) had chronic infection prevalence of less than 1% among children born after vaccine introduction. It was estimated that in the past 25 years immunization programmes in the Western Pacific Region have averted 7,167,128 deaths that would have occurred in the lifetime of children born between 1990 and 2014 if hepatitis B vaccination programmes had not been established. Regional prevalence among children born in 2012 was estimated to be 0.93%, meaning that the Regional hepatitis B control goal was achieved. While additional efforts are needed to further reduce hepatitis B transmission in the region, this study demonstrates the great success of the hepatitis B vaccination efforts in the Western Pacific Region.     

Non-multiresistant methicillin-resistant Staphylococcus aureus bacteraemia in Sydney, Australia: emergence of EMRSA-15, Oceania, Queensland and Western Australian MRSA strains

AIMS: To describe clinical features and molecular epidemiology of non-multiresistant methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia. METHODS: Patients with non-multiresistant MRSA isolated from blood at South Western Area Pathology Service from 1 January 1999 to 31 December 2001 were enrolled. Pulsed field gel electrophoresis, phage typing, and (selected instances) multilocus sequence and staphylococcal cassette chromosome typing was performed. PCR was used to detect Panton-Valentine leukocidin (PVL), toxic shock syndrome toxin-1 (TSST-1), and enterotoxin genes. RESULTS: Sixteen patients were detected: eight with UK EMRSA-15 (ST22-MRSA-IV), three with Oceania (South-West Pacific/Western Samoan phage pattern) (ST30-MRSA-IV), two with WA MRSA-5 (ST8-MRSA-IV), and one each with WA MRSA-1 (ST1-MRSA-IV), Queensland strain (ST93-MRSA-IV), and WA MRSA-15 (ST59-MRSA-IV). Prior hospital admissions occurred with six of the eight patients with UK EMRSA-15, none of the three with Oceania, and three of the five with other strains. Thirteen of 16 patients had underlying disease. Three of the three patients with Oceania strain bacteraemia were Polynesians; 11 of 13 of the others were Caucasians. PVL genes were detected in four of 16 isolates (all Oceania and Queensland strains). entC was detected in two EMRSA-15 strains; entA in one Oceania, two WA MRSA-5 and the WA MRSA-1 strain, with entA and entB in the WA MRSA-15 strain. tst was not detected. CONCLUSIONS: Multiple epidemic strains cause non-multiresistant MRSA bacteraemia. Most patients had risk factors. Oceania and Queensland strains possess the PVL gene.     

Asia Pacific Society of Human Genetics (APSHG) from conception to 2019: 13 years of collaboration to tackle congenital malformation and genetic disorders in Asia

Putting together the reports in this issue that come from a representation of the different countries in Asia presents an opportunity to share the unique story of the Asia Pacific Society of Human Genetics (APSHG), which has provided the authors of many of these articles. This paper, authored by the Past Presidents of the Society, shares glimpses of how medical genetics activities were first organized in the Asia Pacific region and provides interesting corollaries on how under‐developed and developing countries in this part of the world had developed a unique network for exchange and sharing of expertise and resources. Although APSHG was formally registered as a Society in Singapore in 2006, the Society has its origins as far back as in the 1990s with members from different countries meeting informally, exchanging ideas, and collaborating. This treatise documents the story of the experiences of the Society and hopes it will provide inspiration on how members of a genetics community can foster and build a thriving environment to promote this field.     

Comparative prevalence of sensitization to common animal, plant and mould allergens in subjects with asthma, or atopic dermatitis and/or allergic rhinitis living in a tropical environment

BACKGROUND AND OBJECTIVES: Current information suggests that the expression of allergic diseases is determined by the exposure and nature of the allergen. The objectives of the present study were to determine if the nature of allergenic exposition to animal, plant or fungal allergens influenced the clinical manifestations of atopic dermatitis (AD), allergic rhinitis (AR) or asthma (AS) in patients living in a tropical environment. The prevalence and degree of sensitization to these allergens were analysed by age and gender. SUBJECTS AND METHODS: A total of 1496 atopic cases, grouped according to the primary diagnosis of AD or AR or AS, were skin tested using a standardized allergen panel. Participants were categorized by age groups. The atopic index (AI) and mean weal diameter (MWD) as well as the prevalence of positive skin tests were determined for each of the patient groups and compared by age groups. RESULTS: The prevalence of atopy as well as the AI and the MWD peaked at 6-15 years of age and declined thereafter. In all the patients tested, the prevalence of sensitization was, in decreasing order; dust mites 94.3%, cockroach 41.5%, pets 31.5%, plant allergens 31.1% and fungal 19.4%. Eight hundred and ninety-three atopic patients were exclusively sensitized only to animal allergens. Of these, 38.4% had AD, 31.3% had AR and 30.5% with AS. CONCLUSION: These data demonstrate that for patients with AD, AR and AS living in a tropical environment, the prevalence of positive skin reactions to animal allergens is highest followed by plant and fungal allergens. We did not observe any association between the type of allergen and clinical manifestations. The index of atopy was similar for both sexes. The prevalence and degree of sensitization were shown to peak in young adults independent of the allergen in AD and AR patients.     

Suppression substractive hybridisation (SSH) and real time PCR reveal differential gene expression in the Pacific cupped oyster, Crassostrea gigas, challenged with Ostreid herpesvirus 1

Virus-induced genes were identified using suppression subtractive hybridisation (SSH) from Pacific cupped oyster, Crassostrea gigas, haemocytes challenged by OsHV-1. A total of 304 clones from SSH forward library were sequenced. Among these sequences, some homologues corresponded to (i) immune related genes (macrophage express protein, IK cytokine, interferon-induced protein 44 or multicopper oxidase), (ii) apoptosis related genes (Bcl-2) and (iii) cell signalling and virus receptor genes (glypican). Molecular characterization and phylogenic analysis of 3 immune-related genes (macrophage expressed protein, multicopper oxidase and immunoglobulin domain cell adhesion molecule) were performed. Finally, quantitative PCR revealed significant changes in the expression of immune related genes (multicopper oxidase, macrophage expressed protein, myeloid differentiation factor 88 and interferon-induced protein 44) in oysters experimentally challenged with OsHV-1.These findings provide a first basis for studying the role of innate immunity in response to viruses in bivalves and identified genes may serve as markers of interest in breeding programs in order to obtain selected oysters presenting OsHV-1 resistance.     

COVID-19 Vasculopathy: Mounting Evidence for an Indirect Mechanism of Endothelial Injury

Patients with coronavirus disease 2019 (COVID-19) who are critically ill develop vascular complications characterized by thrombosis of small, medium, and large vessels. Dysfunction of the vascular endothelium due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been implicated in the pathogenesis of the COVID-19 vasculopathy. Although initial reports suggested that endothelial injury was caused directly by the virus, recent studies indicate that endothelial cells do not express angiotensin-converting enzyme 2, the receptor that SARS-CoV-2 uses to gain entry into cells, or express it at low levels and are resistant to the infection. These new findings, together with the observation that COVID-19 triggers a cytokine storm capable of injuring the endothelium and disrupting its antithrombogenic properties, favor an indirect mechanism of endothelial injury mediated locally by an augmented inflammatory reaction to infected nonendothelial cells, such as the bronchial and alveolar epithelium, and systemically by the excessive immune response to infection. Herein we review the vascular pathology of COVID-19 and critically discuss the potential mechanisms of endothelial injury in this disease.

Following an initial outbreak of pneumonia in Wuhan, China, in December 2019,¹ coronavirus disease 19 (COVID-19) has spread rapidly worldwide, infecting more than 186 million people (Johns Hopkins Coronavirus Resource Center, https://coronavirus.jhu.edu, last accessed July 12, 2021). Caused by a new type of coronavirus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2),² the COVID-19 pandemic has put a major strain on the healthcare systems, causing a global health crisis of unparalleled proportions in modern times.³ Although most patients have recovered from the infection, many experienced a severe form of the disease that requires hospitalization and intensive care, and >3.2 million people have died. Individuals at greatest risk for the fatal complications of COVID-19 have been the elderly and those with underlying conditions, such as lung disease, hypertension, obesity, and diabetes.⁴Clinical manifestations of COVID-19 in severely ill patients are adult respiratory distress syndrome and multiorgan system failure.^4,5 The clinical course of the disease can be complicated by vascular events, including thrombosis of small, medium, and large blood vessels and thromboembolism.^6,7 Although the primary target of SARS-CoV-2 is the respiratory and alveolar epithelium,⁸ the frequent occurrence of vascular complications in COVID-19 has led to the hypothesis that dysfunction of the endothelium, the inner lining of blood vessels, plays an important role in the progression of this disease into a debilitating and lethal condition.⁹ Two potential mechanisms have been hypothesized to explain how SARS-CoV-2 causes endothelial dysfunction and thrombosis. In the first scenario, SARS-CoV-2 directly infects the endothelium, disrupting its antithrombogenic and barrier properties. The second scenario invokes an indirect mechanism of endothelial injury mediated by the local and systemic inflammatory response to the viral infection.^10,11 In this article, we briefly review the vascular pathology of COVID-19 and critically discuss the proposed mechanisms by which SARS-CoV-2 damages blood vessels, including recent studies that challenge the viral infection of endothelium hypothesis and strongly favor an indirect, inflammation-driven mechanism of endothelial injury.     

HLA-DPA1 and DPB1 polymorphism in four Pacific Islands populations determined by sequencing based typing

Class II HLA-DP antigens are heterodimers comprised of alpha and beta chains coded by HLA-DPA1 and HLA-DPB1 genes. Both genes are polymorphic with substantial variation between different populations world wide. This work describes DPA1 and DPB1 polymorphism in four Pacific Island populations of Cook Islands, Samoa, Tokelau and Tonga, living in New Zealand. Using sequencing based typing four DPA1 alleles and twelve DPB1 alleles were observed in total among the four populations. There are two predominant DPA1 alleles DPA1*01031 and DPA1*02022 and three predominant DPB1 alleles DPB1*02012, DPB1*0401 and DPB1*0501. Fourteen DPA1-DPB1 haplotypes in total are present in these four populations with three predominant haplotypes: DPA1*02022-DPB1*0501, DPA1*01031-DPB1*02012, and DPA1*01031-DPB1*0401. Strong positive and negative disequilibrium was observed for individual DPA1-DPB1 haplotypes. Significant differences in DPA1 and DPB1 allele and haplotype frequencies were observed between Tokelauan and other three populations. Phylogenetic analysis of genetic distances between the four Pacific Island populations and other Asian Oceanian populations have shown that Cook Islanders, Samoans and Tongans are more closely related to Asian populations whereas Tokelauans cluster towards non-Austronesian populations of Papua New Guinea Highlanders and Australian Aborigines.     

Morphological changes in the retina in Pacific ocean salmon <Emphasis Type="Italic">Oncorhynchus masou</Emphasis> fry in response to neutralization of the geomagnetic field in conditions of normal illumination

The studies reported here provide the first demonstration that retinal responses in both the fry of the migratory salmon trout Oncorhynchus masou and the dwarf form of this species changed in conditions of experimental neutralization of the geomagnetic field (GMF); migratory salmon trout fry and dwarves showed different changes. The responses of different types of retinal photoreceptor in migratory salmon trout fry to neutralization of the GMF differed: while rods and double cones perceived neutralization of the GMF as the onset of darkness (the scotopic reaction), single (generally blue-sensitive) cones responded to neutralization of the GMF both as presentation of blue light or (very rarely) ultraviolet irradiation. The retina of dwarf male salmon trout responded to neutralization of the GMF with a double response: rods showed a light (photopic) response, while double (red/green-sensitive) cones produced dark (scotopic) responses. Single (blue-sensitive) cones responded to neutralization of the GMF as bright blue light. Thus, the morphological picture of the retina in dwarf male salmon trout in these experimental conditions corresponds to the perception of blue light. The initial conditions were different--normal diffuse daylight with a brightness of about 7.5 Lx. It is likely that neutralization of the magnetic field had no effect on rods, while double, red-green, cones responded as to darkness, i.e., the fish did not perceive red or green light in the visible spectrum, but perceived only blue and, possibly, ultraviolet light by means of central blue-sensitive and accessory cones. Thus, these experiments demonstrated that in conditions of normal daylight illumination, retinal photoreceptors in salmon fry respond to changes in the earth's magnetic field, i.e., objectively function as magnetoreceptors.