Seroevidence of SARS-CoV-2 spillback to rodents in Sarawak, Malaysian Borneo.

BACKGROUND: SARS-CoV-2 is believed to have originated from a spillover event, where the virus jumped from bats to humans, leading to an epidemic that quickly escalated into a pandemic by early 2020. Despite the implementation of various public health measures, such as lockdowns and widespread vaccination efforts, the virus continues to spread. This is primarily attributed to the rapid emergence of immune escape variants and the inadequacy of protection against reinfection. Spillback events were reported early in animals with frequent contact with humans, especially companion, captive, and farmed animals. Unfortunately, surveillance of spillback events is generally lacking in Malaysia. Therefore, this study aims to address this gap by investigating the presence of SARS-CoV-2 neutralising antibodies in wild rodents in Sarawak, Malaysia. RESULTS: We analysed 208 archived plasma from rodents collected between from 2018 to 2022 to detect neutralising antibodies against SARS-CoV-2 using a surrogate virus neutralisation test, and discovered two seropositive rodents (Sundamys muelleri and Rattus rattus), which were sampled in 2021 and 2022, respectively. CONCLUSION: Our findings suggest that Sundamys muelleri and Rattus rattus may be susceptible to natural SARS-CoV-2 infections. However, there is currently no evidence supporting sustainable rodent-to-rodent transmission.

Prevalence and risk factors associated with alcohol consumption among indigenous people in Sabah Borneo Island.

OBJECTIVES: In this study, we aimed to determine the prevalence and risk factors of alcohol use among a cohort of population in Sabah. DESIGN: This is a prospective, cohort study involving rural community residents. SETTING: Rural community resident at Bingkor, Keningau, Sabah. PARTICIPANTS: 363 individuals aged 13 years old and above. INTERVENTION: Community-based participatory research to determine the prevalence and risk factors associated with alcohol use. MAIN OUTCOME MEASURES: Measurement of alcohol use using Alcohol Use Disorders Identification Test (AUDIT) and assessment of psychiatric morbidity using Mini International Neuropsychiatric Interview (MINI) questionnaires. RESULTS: Most alcohol drinkers aged between 36-45 years old, followed by 26-35 years old and 46-55 years old. Interestingly, there are almost similar female to male ratio. Most were Kadazan-Dusun ethnic, non-Muslims, and married. Although only less than a third of the participants received tertiary education, the majority were working. Based on the findings, being a male, non-Muslim and having an obsessive-compulsive disorder (OCD) (current) posed a significantly higher risk of alcohol consumption. CONCLUSION: A worryingly high prevalence of hazardous alcohol consumption among the locals is reported. There is a need for population-wide intervention towards preventive measures based on the identified risk factors for hazardous alcohol use.

Malaria distribution and performance of malaria diagnostic methods in Malaysia (1980-2019): a systematic review.

BACKGROUND: Malaysia has already achieved remarkable accomplishments in reaching zero indigenous human malaria cases in 2018. Prompt malaria diagnosis, surveillance and treatment played a key role in the country's elimination success. Looking at the dynamics of malaria distribution during the last decades might provide important information regarding the potential challenges of such an elimination strategy. This study was performed to gather all data available in term of prevalence or incidence on Plasmodium infections in Malaysia over the last four decades. METHODS: A systematic review of the published English literature was conducted to identify malaria distribution from 1980 to June 2019 in Malaysia. Two investigators independently extracted data from PubMed, Scopus, Web of Science and Elsevier databases for original papers. RESULTS: The review identified 46 epidemiological studies in Malaysia over the 39-year study period, on which sufficient information was available. The majority of studies were conducted in Malaysia Borneo (31/46; 67.4%), followed by Peninsular Malaysia (13/46; 28.3%) and in both areas (2/46; 4.3%). More than half of all studies (28/46; 60.9%) were assessed by both microscopy and PCR. Furthermore, there was a clear trend of decreases of all human malaria species with increasing Plasmodium knowlesi incidence rate throughout the year of sampling period. The summary estimates of sensitivity were higher for P. knowlesi than other Plasmodium species for both microscopy and PCR. Nevertheless, the specificities of summary estimates were similar for microscopy (40-43%), but varied for PCR (2-34%). CONCLUSIONS: This study outlined the epidemiological changes in Plasmodium species distribution in Malaysia. Malaria cases shifted from predominantly caused by human malaria parasites to simian malaria parasites, which accounted for the majority of indigenous cases particularly in Malaysia Borneo. Therefore, malaria case notification and prompt malaria diagnosis in regions where health services are limited in Malaysia should be strengthened and reinforced to achieving the final goal of malaria elimination in the country.

Entamoeba histolytica infections in wild and semi-wild orangutans in Sumatra and Kalimantan.

Key to the success of orangutan conservation management practices is the prevention of the introduction of infectious diseases to the remaining populations. Previous reports of Entamoeba spp. positive orangutans are of concern as Entamoeba spp. infection has been linked to morbidity and mortality in primates. It remains to be determined if the Entamoeba species infecting orangutans is the pathogenic Entamoeba histolytica. Orangutan fecal samples have been collected from orangutans from sites in Sumatra (Bukit Lawang, Ketambe, and Suaq, 241 samples from 64 individuals), and two sites in Kalimantan (Sebangau and Tuanan, 129 samples from 39 individuals). All samples were from wild orangutans except for a proportion from Sumatra which were from semi-wild (108 samples, 10 individuals). E. histolytica-specific nested PCR assays were carried out on the fecal samples. A total of 36 samples from 17 individuals tested positive for E. histolytica. When compared with published sequences using NCBI BLAST the E. histolytica positive samples showed a 98-99% concordance. The majority (76%, n = 36) of the positive isolates came from semi-wild orangutans in Bukit Lawang. This study supports the growing body of evidence that contact with humans is an important risk factor for infection of wild primates with E. histolytica.

Defining the ecological and evolutionary drivers of Plasmodium knowlesi transmission within a multi-scale framework.

Plasmodium knowlesi is a zoonotic malaria parasite normally residing in long-tailed and pig-tailed macaques (Macaca fascicularis and Macaca nemestrina, respectively) found throughout Southeast Asia. Recently, knowlesi malaria has become the predominant malaria affecting humans in Malaysian Borneo, being responsible for approximately 70% of reported cases. Largely as a result of anthropogenic land use changes in Borneo, vectors which transmit the parasite, along with macaque hosts, are both now frequently found in disturbed forest habitats, or at the forest fringes, thus having more frequent contact with humans. Having access to human hosts provides the parasite with the opportunity to further its adaption to the human immune system. The ecological drivers of the transmission and spread of P. knowlesi are operating over many different spatial (and, therefore, temporal) scales, from the molecular to the continental. Strategies to prevent and manage zoonoses, such as P. knowlesi malaria require interdisciplinary research exploring the impact of land use change and biodiversity loss on the evolving relationship between parasite, reservoir hosts, vectors, and humans over multiple spatial scales.

Helminth parasites occurrence in wild proboscis monkeys (Nasalis larvatus), endemic primates to Borneo Island.

BACKGROUND: Nasalis larvatus are well-known attraction for tourists in the mangrove forest of Bako National Park (BNP). Little is known regarding the infestation of helminth parasites in proboscis monkeys. Therefore, the objectives of this study are to determine the prevalence species of major helminth parasites of public health importance in proboscis monkeys in BNP. METHODS: A total of 65 faecal samples screened for helminth parasites via sodium nitrate floatation and faecal sedimentation techniques. RESULTS: A total of 14 helminth parasite species comprising of eight genera of nematodes, two species of cestodes and two trematodes were identified. Eggs of Trichuris trichiura were the most frequently encountered in proboscis monkeys. CONCLUSION: This is the first survey on the fauna of helminth parasites of proboscis monkeys living in mangrove forests, and therefore, it implies the important baseline information that increases our current knowledge for future research regarding parasite-host ecology in primates.

Gastrointestinal parasites of zoonotic importance observed in the wild, urban, and captive populations of non-human primates in Malaysia.

BACKGROUND: A study was undertaken to determine gastrointestinal (GI) parasites commonly found in Malaysia's non-human primates (NHP) living in three different types of populations (wild, urban, and captive) and the basis of major GI parasites of zoonotic importance. METHODS: A total of 308 samples was collected and microscopically screened from the NHP in the wild (n = 163), urban (n = 76), and captive (n = 69) populations. The samples were taken from 12 species of local NHPs. RESULTS: At least, 44 species of GI parasites comprising of protozoans (seven species), nematodes (26 species), cestodes (five species), trematodes (five species), and pentastomida (one species) were detected. There were no significant differences for the overall prevalence and no great differences in GI parasite species among the wild, urban, and captive NHP populations. CONCLUSION: The most common GI parasite was Ascaris spp. (49.7%), followed by Oesophagostomum spp. (26.9%), and 31 species discovered in this study are of known public health importance.

Invasive Salmonella infections among children in Bintulu, Sarawak, Malaysian Borneo: a 6-year retrospective review.

BACKGROUND: Invasive Salmonella infections result in significant morbidity and mortality in developing countries. In Asia, typhoid and paratyphoid fever are reported to be the major invasive Salmonella infections, while invasive non-typhoidal Salmonella (iNTS) infections are believed to be uncommon. Data from Sarawak, in Malaysian Borneo, are limited. METHODS: A retrospective study identifying all children aged < 15 years with invasive Salmonella infections from 2011 to 2016 was conducted in Bintulu Hospital in Sarawak. Population incidences, clinical and bacterial characteristics were examined. RESULTS: Forty-four patients were identified during the 6-year study period: 43 had iNTS infection and 1 had typhoid fever. The average annual iNTS incidence was 32.4 per 100,000 children aged < 5 years. None of the children had malaria or HIV infection, and only 7% were severely malnourished. Salmonella Enteritidis and Salmonella Java were the commonest NTS serovars identified. Pneumonia was the most common manifestation of iNTS disease, present in 20 (47%) children. Other manifestations included gastroenteritis, fever without a source, septic arthritis and meningitis. Salmonella Enteritidis was identified in 76% of those with pneumonia, significantly more frequently than in children with other manifestations. Over 25% of children with iNTS developed severe disease and nearly 10% suffered long term morbidity or mortality. While 78% of Salmonella Java isolates were multi-drug resistant, nearly all other isolates were susceptible to most antimicrobials, including ampicillin. CONCLUSIONS: Bintulu Division in Sarawak observed a very high incidence of childhood iNTS infections. Enteric fever was uncommon. The epidemiology of invasive Salmonella infections in Malaysian Borneo differs considerably from that of neighbouring countries in Asia.

Absence of Plasmodium inui and Plasmodium cynomolgi, but detection of Plasmodium knowlesi and Plasmodium vivax infections in asymptomatic humans in the Betong division of Sarawak, Malaysian Borneo.

BACKGROUND: Plasmodium knowlesi, a simian malaria parasite, has become the main cause of malaria in Sarawak, Malaysian Borneo. Epidemiological data on malaria for Sarawak has been derived solely from hospitalized patients, and more accurate epidemiological data on malaria is necessary. Therefore, a longitudinal study of communities affected by knowlesi malaria was undertaken. METHODS: A total of 3002 blood samples on filter paper were collected from 555 inhabitants of 8 longhouses with recently reported knowlesi malaria cases in the Betong Division of Sarawak, Malaysian Borneo. Each longhouse was visited bimonthly for a total of 10 times during a 21-month study period (Jan 2014-Oct 2015). DNA extracted from blood spots were examined by a nested PCR assay for Plasmodium and positive samples were then examined by nested PCR assays for Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, Plasmodium knowlesi, Plasmodium cynomolgi and Plasmodium inui. Blood films of samples positive by PCR were also examined by microscopy. RESULTS: Genus-specific PCR assay detected Plasmodium DNA in 9 out of 3002 samples. Species-specific PCR identified 7 P. knowlesi and one P. vivax. Malaria parasites were observed in 5 thick blood films of the PCR positive samples. No parasites were observed in blood films from one knowlesi-, one vivax- and the genus-positive samples. Only one of 7 P. knowlesi-infected individual was febrile and had sought medical treatment at Betong Hospital the day after sampling. The 6 knowlesi-, one vivax- and one Plasmodium-infected individuals were afebrile and did not seek any medical treatment. CONCLUSIONS: Asymptomatic human P. knowlesi and P. vivax malaria infections, but not P. cynomolgi and P. inui infections, are occurring within communities affected with malaria.

Highly Divergent Dengue Virus Type 2 in Traveler Returning from Borneo to Australia.

Dengue virus type 2 was isolated from a tourist who returned from Borneo to Australia. Phylogenetic analysis identified this virus as highly divergent and occupying a basal phylogenetic position relative to all known human and sylvatic dengue virus type 2 strains and the most divergent lineage not assigned to a new serotype.

Helicobacter pylori Infection Rates in Patients Undergoing Endoscopy in the Interior of Borneo.

INTRODUCTION: Very limited data are available on the Helicobacter pylori infection among the population of interior Borneo. We aimed to investigate the H. pylori infection rate among an endoscoped interior Borneo population and to report the differences between the infected and noninfected patients. METHODS: We retrospectively analyzed the data of the rapid urease test (RUT) records in Endoscopy Unit Hospital Keningau from January 2009 to May 2014. Student's t-test, chi-square test or Fisher's exact test were used accordingly. Multiple logistic regression analysis was used to identify independent risk factors for H. pylori infection. Birth cohort was analyzed against H. pylori infection rate with chi-square test. RESULTS: Overall, there were 215 of 774 (27.8%) positive RUTs. Patients with H. pylori infection were younger (47.66 ± 14.93 vs 50.50 ± 15.02 years, p = .019), more likely to be female (OR = 1.54, 95% CI 1.12-2.13, p = .008) and originated from the Pensiangan district (OR = 1.63, 95% CI 1.01-2.64, p = .047). Chinese patients were less likely infected with H. pylori (OR = 0.36, 95% CI 0.16-0.80, p = .013). Birth cohort was significantly associated with H. pylori infection rate (χ(2) (7) = 14.71, p = .040) with an increasing trend of H. pylori infection rate in patients born later (χ(2) (1) = 5.26, p = .022). CONCLUSION: The overall H. pylori infection rate in this population was unexpectedly low. Accordingly, it may be a recent arrival in this community. Gender, age, dietary practice, socioeconomic status, and ethnicity were among the factors associated with H. pylori infection.

Epidemiological Characteristics of Strongyloidiasis in Inhabitants of Indigenous Communities in Borneo Island, Malaysia.

Epidemiological study on strongyloidiasis in humans is currently lacking in Malaysia. Thus, a cross-sectional study was carried out to determine the prevalence of Strongyloides stercoralis infection among the inhabitants of longhouse indigenous communities in Sarawak. A single stool and blood sample were collected from each participant and subjected to microscopy, serological and molecular techniques. Five species of intestinal parasites were identified by stool microscopy. None of the stool samples were positive for S. stercoralis. However, 11% of 236 serum samples were seropositive for strongyloidiasis. Further confirmation using molecular technique on stool samples of the seropositive individuals successfully amplified 5 samples, suggesting current active infections. The prevalence was significantly higher in adult males and tended to increase with age. S. stercoralis should no longer be neglected in any intestinal parasitic survey. Combination of more than 1 diagnostic technique is necessary to increase the likelihood of estimating the 'true' prevalence of S. stercoralis.

Factors associated with physical inactivity among female and male rural adolescents in Borneo - a cross-sectional study.

Rural communities have shown marked increase in metabolic syndrome among young people, with physical inactivity as one of the main contributing factors. This study aimed to determine factors associated with physical inactivity among male and female rural adolescents in a sample of schools in Malaysia. A cross-sectional study was conducted among 145 students aged 13-15 years. Data on socio-demographic, health-related, and psychosocial factors (perceived barriers, self-efficacy, social influences) were collected using a self-administered questionnaire. Anthropometric measurement was taken to generate body mass index (BMI)-for-age, while physical activity (PA) level was assessed using pedometers. The mean steps per day was 6251.37 (SD=3085.31) with males reported as being more active. About 27% of the respondents were either overweight or obese, with more females in this group. There was no significant difference in steps among males and females (p=0.212), and nutritional status (BMI-for-age) (p=0.439). Females consistently scored higher in most items under perceived barriers, but had significantly lower scores in self-efficacy's items. Males were more influenced by peers in terms of PA (p<0.001) and were more satisfied with their body parts (p=0.047). A significantly higher body size discrepancy score was found among females (p=0.034, CI -0.639, -0.026). PA level was low and almost one-third of the respondents were overweight and obese. Female students faced more barriers and had lower self-efficacy with regards PA. Based on the findings, it is recommended that interventions focus on reducing barriers while increasing support for PA. This is particularly important in improving the health status of the youth, especially among the females.

Apparent mortality as a result of an elevated parasite infection in Presbytis rubicunda.

We provide the first parasite assessment of wild red langurs (Presbytis rubicunda). Seven helminth taxa and 4 protozoa were recovered from faecal samples. We report the details of the death of an adult female red langur with potential association of an elevated parasite infection. There is a paucity of published literature on red langurs and nothing is known of the factors affecting interspecific parasite transmission and disease spread between other primate species. Parasites may be substantial determinants of host health and may present a significant influence on the survival and reproduction of individuals and the subsequent fecundity of populations. Further research into the connection of parasite burden with individual deaths and potential population declines is recommended for monitoring population health.

Epidemiology of Uterine Cancer in Sarawak, Borneo, A 20-Year Review.

OBJECTIVE: This study aimed to determine the epidemiology of uterine cancer in Sarawak, Malaysia, using data from a population-based cancer registry. METHODS: The study population included all women diagnosed with uterine cancer in Sarawak, Malaysia between January 1996 and December 2015. Data on demographic and clinical characteristics were obtained from the Sarawak Cancer Registry. The crude incidence rate, age-standardized incidence rate (ASR), and incidence risk ratios (IRR) were calculated. Joinpoint regression analyses were performed to assess trends in incidence rates. RESULTS: A total of 811 women were diagnosed with primary uterine cancer during the study period. The overall crude incidence rate for uterine cancer in Sarawak for the period 1996-2015 was 3.7 per 100,000. The ASR was 4.4 per 100,000 with a 95% CI (4.1-4.8). The ASR in 2011-2015 is 1.6 times higher than the ASR of uterine cancer in 1996-2000. Higher incidence rates were observed in women aged 40-59 years and those aged 60 years and above. Chinese women had the highest ASR, followed by Malay and Iban women. Joinpoint regression analyses showed a significant increase in cases of uterine cancer among all ethnic groups and age groups. CONCLUSION: The incidence of primary uterine cancer in Sarawak, Malaysia, has increased over the past 20 years, with higher incidence rates observed in older age groups and among Chinese women. The findings suggest the need for continued efforts to improve the prevention, early detection, and treatment of uterine cancer in Sarawak.

Plasmodium knowlesi: reservoir hosts and tracking the emergence in humans and macaques.

Plasmodium knowlesi, a malaria parasite originally thought to be restricted to macaques in Southeast Asia, has recently been recognized as a significant cause of human malaria. Unlike the benign and morphologically similar P. malariae, these parasites can lead to fatal infections. Malaria parasites, including P. knowlesi, have not yet been detected in macaques of the Kapit Division of Malaysian Borneo, where the majority of human knowlesi malaria cases have been reported. In order to extend our understanding of the epidemiology and evolutionary history of P. knowlesi, we examined 108 wild macaques for malaria parasites and sequenced the circumsporozoite protein (csp) gene and mitochondrial (mt) DNA of P. knowlesi isolates derived from macaques and humans. We detected five species of Plasmodium (P. knowlesi, P. inui, P. cynomolgi, P. fieldi and P. coatneyi) in the long-tailed and pig-tailed macaques, and an extremely high prevalence of P. inui and P. knowlesi. Macaques had a higher number of P. knowlesi genotypes per infection than humans, and some diverse alleles of the P. knowlesi csp gene and certain mtDNA haplotypes were shared between both hosts. Analyses of DNA sequence data indicate that there are no mtDNA lineages associated exclusively with either host. Furthermore, our analyses of the mtDNA data reveal that P. knowlesi is derived from an ancestral parasite population that existed prior to human settlement in Southeast Asia, and underwent significant population expansion approximately 30,000-40,000 years ago. Our results indicate that human infections with P. knowlesi are not newly emergent in Southeast Asia and that knowlesi malaria is primarily a zoonosis with wild macaques as the reservoir hosts. However, ongoing ecological changes resulting from deforestation, with an associated increase in the human population, could enable this pathogenic species of Plasmodium to switch to humans as the preferred host.

High prevalence of mutation in the Plasmodium falciparum dhfr and dhps genes in field isolates from Sabah, Northern Borneo.

BACKGROUND: Sulphadoxine-pyrimethamine (SP) has been in use for the treatment of uncomplicated falciparum malaria in Malaysia since the 1970s and is still widely employed in spite of widespread clinical resistance. Resistance to SP is known to be mediated by mutations in the pfdhfr and pfdhps genes. The aim of the present study was to investigate the distribution of pfdhfr and pfdhps gene polymorphism in Plasmodium falciparum field isolates from Kalabakan, Sabah, in northern Borneo. METHODS: A total number of 619 individuals were screened from 23 study sites of which 31 were positive for P. falciparum. Analysis of restriction fragment length polymorphisms (RFLP) was used to identify polymorphism in the pfdhfr and pfdhps genes at positions 16, 51, 59, 108, 164 and 437, 540, 581, respectively. RESULTS: All samples had at least one mutation in each of the genes associated with drug resistance. The prevalence of pfdhfr 59arg, 164leu and 108asn were 100%, 80.65% and 58.06%, respectively. Pfdhps mutants 437gly and 581gly accounted for 100% and 74.19% respectively. In pfdhfr, the most common mutant genotypes were combination 59arg + 164leu (22.58%) and 59arg + 108asn + 164leu (51.61%). In pfdhps the most common genotype was 437gly + 581gly (74.19%). One individual (3.22%) harboured parasites with four pfdhfr (16 val + 59arg + 108asn + 164leu) and two pfdhps (437gly + 581gly) mutations. The highest quintuple pfdhfr/pfdhps (41.94%) was three pfdhfr (59arg + 108asn + 164gly) and two pfdhps (437gly + 581gly). CONCLUSION: The data suggest a high prevalence of genetic variations conferring resistance to SP which can predict treatment failure before becoming clinically evident. In areas like this, the use of SP may no longer be indicated.

High incidence of nasopharyngeal cancer: similarity for 60% of mitochondrial DNA signatures between the Bidayuhs of Borneo and the Bai-yue of Southern China.

Populations in Southern China (Bai-yue) and Borneo (Bidayuh) with high incidence of nasopharyngeal cancer(NPC) share similar mitochondrial DNA signatures, supporting the hypothesis that these two populations may share the same genetic predisposition for NPC, which may have first appeared in a common ancestral reference population before the sea levels rose after the last ice age.

High incidence of asymptomatic cases during an outbreak of Plasmodium malariae in a remote village of Malaysian Borneo.

An outbreak of Plasmodium malariae occurred in Sonsogon Paliu village in the remote area of Ulu Bengkoka sub-district of Kota Marudu, Northern Sabah, Malaysian Borneo from July through August 2019. This was the first outbreak of malaria in this village since 2014. On 11th July 2019 the Kota Kinabalu Public Health Laboratory notified the Kota Marudu District Health Office of a Polymerase Chain Reaction (PCR) positive case of P. malariae. This index case was a male from Sulawesi, Indonesia working for a logging company operating in Sonsogon Paliu. During the resulting outbreak, a total of 14 symptomatic cases were detected. All of these cases were positive by thick and thin blood smear examination, and also by PCR. During the outbreak, a mass blood survey screening was performed by light-microscopy and PCR. A total of 94 asymptomatic villagers 31 (33.0%) were PCR positive but thick and thin blood smear negative for P. malariae. Both symptomatic and asymptomatic cases received treatment at the district hospital. When symptomatic and asymptomatic cases were considered together, males (29/45. 64.5%) were infected more than females (16/45, 35.6%), the male:female ratio being 1.8:1. Adults were the predominant age group infected (22/45, 48.9%) followed by adolescents (19/45, 42.2%) and children under five years of age (4/45, 8.9%). This report illustrates that symptomatic and submicroscopic cases pose a challenge during P. malariae outbreaks and that PCR is a valuable tool for their identification. The rapid identification and control of imported malaria is crucial for the continued control of malaria in Malaysia.