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Fulltext Nipah@20: Lessons Learned from Another Virus with Pandemic Potential

Gómez Román R, Wang LF, Lee B, Halpin K, de Wit E, Broder CC, et al.

mSphere, 2020 07 08;5(4).
PMID: 32641430 DOI: 10.1128/mSphere.00602-20

Nipah disease is listed as one of the WHO priority diseases that pose the greatest public health risk due to their epidemic potential. More than 200 experts from around the world convened in Singapore last year to mark the 20th anniversary of the first Nipah virus outbreaks in Malaysia and Singapore. Most of these experts are now involved in responding to the coronavirus disease 2019 (COVID-19) pandemic. Here, members of the Organizing Committee of the 2019 Nipah Virus International Conference review highlights from the Nipah@20 Conference and reflect on key lessons learned from Nipah that could be applied to the understanding of the COVID-19 pandemic and to preparedness against future emerging infectious diseases (EIDs) of pandemic potential.

Matched MeSH terms: Zoonoses/epidemiology
Isolation of SARS-CoV-2-related coronavirus from Malayan pangolins

Xiao K, Zhai J, Feng Y, Zhou N, Zhang X, Zou JJ, et al.

Nature, 2020 07;583(7815):286-289.
PMID: 32380510 DOI: 10.1038/s41586-020-2313-x

The current outbreak of coronavirus disease-2019 (COVID-19) poses unprecedented challenges to global health1. The new coronavirus responsible for this outbreak-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-shares high sequence identity to SARS-CoV and a bat coronavirus, RaTG132. Although bats may be the reservoir host for a variety of coronaviruses3,4, it remains unknown whether SARS-CoV-2 has additional host species. Here we show that a coronavirus, which we name pangolin-CoV, isolated from a Malayan pangolin has 100%, 98.6%, 97.8% and 90.7% amino acid identity with SARS-CoV-2 in the E, M, N and S proteins, respectively. In particular, the receptor-binding domain of the S protein of pangolin-CoV is almost identical to that of SARS-CoV-2, with one difference in a noncritical amino acid. Our comparative genomic analysis suggests that SARS-CoV-2 may have originated in the recombination of a virus similar to pangolin-CoV with one similar to RaTG13. Pangolin-CoV was detected in 17 out of the 25 Malayan pangolins that we analysed. Infected pangolins showed clinical signs and histological changes, and circulating antibodies against pangolin-CoV reacted with the S protein of SARS-CoV-2. The isolation of a coronavirus from pangolins that is closely related to SARS-CoV-2 suggests that these animals have the potential to act as an intermediate host of SARS-CoV-2. This newly identified coronavirus from pangolins-the most-trafficked mammal in the illegal wildlife trade-could represent a future threat to public health if wildlife trade is not effectively controlled.

Matched MeSH terms: Zoonoses/transmission; Zoonoses/virology
Identifying SARS-CoV-2-related coronaviruses in Malayan pangolins

Lam TT, Jia N, Zhang YW, Shum MH, Jiang JF, Zhu HC, et al.

Nature, 2020 07;583(7815):282-285.
PMID: 32218527 DOI: 10.1038/s41586-020-2169-0

The ongoing outbreak of viral pneumonia in China and across the world is associated with a new coronavirus, SARS-CoV-21. This outbreak has been tentatively associated with a seafood market in Wuhan, China, where the sale of wild animals may be the source of zoonotic infection2. Although bats are probable reservoir hosts for SARS-CoV-2, the identity of any intermediate host that may have facilitated transfer to humans is unknown. Here we report the identification of SARS-CoV-2-related coronaviruses in Malayan pangolins (Manis javanica) seized in anti-smuggling operations in southern China. Metagenomic sequencing identified pangolin-associated coronaviruses that belong to two sub-lineages of SARS-CoV-2-related coronaviruses, including one that exhibits strong similarity in the receptor-binding domain to SARS-CoV-2. The discovery of multiple lineages of pangolin coronavirus and their similarity to SARS-CoV-2 suggests that pangolins should be considered as possible hosts in the emergence of new coronaviruses and should be removed from wet markets to prevent zoonotic transmission.

Matched MeSH terms: Zoonoses/virology
Fulltext Seasonal Filarial Infections and Their Black Fly Vectors in Chiang Mai Province, Northern Thailand

Aupalee K, Saeung A, Srisuka W, Fukuda M, Streit A, Takaoka H

Pathogens, 2020 Jun 25;9(6).
PMID: 32630410 DOI: 10.3390/pathogens9060512

The transmission of zoonotic filarial parasites by black flies has so far been reported in the Chiang Mai and Tak provinces, Thailand, and the bites of these infected black flies can cause a rare disease-human zoonotic onchocerciasis. However, species identification of the filarial parasites and their black fly vectors in the Chiang Mai province were previously only based on a morphotaxonomic analysis. In this study, a combined approach of morphotaxonomic and molecular analyses (mitochondrial cox1, 12S rRNA, and nuclear 18S rRNA (SSU HVR-I) genes) was used to clarify the natural filarial infections in female black flies collected by using human and swine baits from two study areas (Ban Lek and Ban Pang Dang) in the Chiang Mai province from March 2018 to January 2019. A total of 805 and 4597 adult females, belonging to seven and nine black fly taxa, were collected from Ban Lek and Ban Pang Dang, respectively. At Ban Lek, four of the 309 adult females of Simulium nigrogilvum were positive for Onchocerca species type I in the hot and rainy seasons. At Ban Pang Dang, five unknown filarial larvae (belonging to the same new species) were detected in Simulium sp. in the S. varicorne species-group and in three species in the S. asakoae species-group in all seasons, and three non-filarial larvae of three different taxa were also found in three females of the S. asakoae species-group. This study is the first to molecularly identify new filarial species and their vector black fly species in Thailand.

Matched MeSH terms: Zoonoses
Fulltext Data on ectoparasites infestation on small mammals from different habitats in east-coast Peninsular Malaysia

Ahmad NII, Rahim NAA, Roslan A, Adrus M, Ahamad M, Hassan M, et al.

Data Brief, 2020 Jun;30:105621.
PMID: 32395585 DOI: 10.1016/j.dib.2020.105621

This data article presents on the ectoparasites infestation on small mammals in Peninsular Malaysia. The dataset on ectoparasites infestation is important because it raises a major medical concern regarding the spread of potentially zoonotic disease from wildlife to human. Tick and chigger are the primary ectoparasites as reservoirs of vector-borne diseases found on small mammals in Malaysia. These small mammals that are infested with ectoparasites occupy various types of habitats, including human settlements, could be of community health risks as the carriers of potentially zoonotic diseases. Field samplings were conducted from February 2015 to February 2016 in three different ecological habitats of mixed dipterocarp forest, coastal forest and insular forest, in Terengganu, Malaysia. A total of 35 and 22 species of bats and rodents respectively were captured and examined for ectoparasites. Twenty-three species of bats and 16 species of small mammal were recorded as hosts for at least one species of ectoparasites. These findings show that the highest ectoparasite infestation occurred on bat community.

Matched MeSH terms: Zoonoses
Fulltext Epidemiology of Taenia saginata taeniosis/cysticercosis: a systematic review of the distribution in East, Southeast and South Asia

Eichenberger RM, Thomas LF, Gabriël S, Bobić B, Devleesschauwer B, Robertson LJ, et al.

Parasit Vectors, 2020 May 07;13(1):234.
PMID: 32381027 DOI: 10.1186/s13071-020-04095-1

BACKGROUND: Taenia saginata is an important zoonotic parasite, causing taeniosis in humans and cysticercosis in bovines, the latter being a significant concern for the global beef industry. Many countries in East, Southeast and South Asia are experiencing rapid economic growth, and an increasing number of people in these countries are dependent on the livestock industry. Currently, however, an overview of the prevalence of T. saginata in this region is lacking. In this review, we analysed the available literature on T. saginata taeniosis and bovine cysticercosis for East, Southeast and South Asia.
METHODS: A systematic review was conducted, based on both published and grey literature. Articles published between 1990 and 2017 were mined for information on the occurrence, prevalence, and geographical distribution of T. saginata taeniosis and bovine cysticercosis in East, Southeast and South Asia.
RESULTS: The presence of T. saginata was described in 15 of 27 countries of the region, including Afghanistan, Cambodia, China, India, Indonesia, Japan, Lao PDR, Malaysia, Mongolia, Nepal, Pakistan, Philippines, South Korea, Thailand and Vietnam. The only country that reported an absence of T. saginata is Japan, although sporadic reports of imported cases and unconfirmed reports of autochthonous infections were identified. Nationwide surveys of taeniosis with systematic sample collection and high sample numbers were available for Cambodia, China, Lao PDR, and South Korea, although speciation of Taenia was not always performed. Regional prevalence of taeniosis and bovine cysticercosis in endemic regions ranged between 0.02-42.6%, and 0.76-46.7%, respectively. However, data for bovine cysticercosis were only available for five countries (Japan, Lao PDR, Mongolia, Pakistan and Vietnam).
CONCLUSIONS: The data indicate a widespread occurrence of T. saginata throughout East, Southeast and South Asia. Identification of Taenia spp. in human infections was frequently not performed, leading to gaps in knowledge about the distribution of human tapeworm infections, mainly in regions where different human Taenia species co-occur. A high prevalence of T. saginata taeniosis and bovine cysticercosis may reflect insufficiencies in sanitation, limited health education standards, and insufficient food safety measures. Therefore, there is a need to improve local surveillance, notification, and overall control systems.

Matched MeSH terms: Zoonoses/epidemiology
Molecular detection of porcine Enterocytozoon bieneusi infection in Peninsular Malaysia and epidemiological risk factors associated with potentially zoonotic genotypes

Ruviniyia K, Abdullah DA, Sumita S, Lim YAL, Ooi PT, Sharma RSK

Parasitol Res, 2020 May;119(5):1663-1674.
PMID: 32219552 DOI: 10.1007/s00436-020-06648-w

Enterocytozoon bieneusi is an emerging opportunistic pathogen infecting humans, and both domestic and wild pigs are known to harbour zoonotic genotypes. There remains a paucity of information on the prevalence and epidemiology of this enteropathogen in Southeast Asia. The present study was undertaken to determine the molecular prevalence and risk factors associated with E. bieneusi infection among commercially farmed pigs in Malaysia. Faecal samples were collected from 450 pigs from 15 different farms and subjected to nested PCR amplification of the ribosomal internal transcribed spacer (ITS) gene of E. bieneusi. Phylogenetic analysis involved 28 nucleotide sequences of the ITS region of E. bieneusi. An interviewer-administered questionnaire provided information on the animal hosts, farm management systems and environmental factors and was statistically analysed to determine the risk factors for infection. The prevalence of E. bieneusi infection was relatively high (40.7%). The highest prevalence (51.3%) was recorded among the piglets, while the adults showed the lowest level of infection (31.3%). Multivariate analysis indicated that age of the pigs, distance of the farm from human settlement and farm management system were significant risk factors of infection. Three genotypes (EbpA, EbpC and Henan-III) detected among the pigs are potentially zoonotic. The high prevalence of E. bieneusi among locally reared pigs, the presence of zoonotic genotypes and the spatial distribution of pig farms and human settlements warrant further investigation on the possibility of zoonotic transmission.

Matched MeSH terms: Zoonoses/epidemiology
Validation of Occupational Zoonotic Disease Questionnaire Using Fuzzy Delphi Method

Sulaiman HF, Ismail R, Mohd Yusoff H, Anuar N, Mohd Jamil MR, Daud F

J Agromedicine, 2020 04;25(2):166-172.
PMID: 31533524 DOI: 10.1080/1059924X.2019.1666763

Objective: The Fuzzy Delphi Method (FDM) is one of the phases in Design and Development Research (DDR). It is a systematic method for tool development and validation. This article aims to validate an occupational zoonotic disease questionnaire using this technique. DDR is applied going through phase 1 (needs analysis), phase 2 (development and design), and phase 3 (usability).Method: In phase 1, information about safe work practices and occupational zoonotic exposure was obtained from discussions to verify predetermined domains as stated in The National Park Service survey on zoonotic disease exposure and risk. In phase 2, agreement from 14 experts about the domains was obtained using the FDM. In phase 3, a cognitive debriefing was performed to determine its usability for future studies. A total of five superior domains were verified, and their items were adapted. All domains and their items were submitted to experts to obtain consensus agreement.Results: A total of 31 (96.9%) passed the Triangle of Fuzzy Numbers and Defuzzification process with acceptable consensus agreement (78.8-91.9%) and threshold d value (0.07-0.14). Only four veterinarians were needed for cognitive debriefing to achieve the point of saturation.Conclusion: FDM in DDR is suitable to be applied by various professions for tool validation, as it is doable and cost and time effective. The Occupational Zoonotic Disease Questionnaire is now ready to be used for future studies in Malaysia.

Matched MeSH terms: Zoonoses/etiology; Zoonoses/epidemiology*
Fulltext Potential Factors Influencing Repeated SARS Outbreaks in China

Sun Z, Thilakavathy K, Kumar SS, He G, Liu SV

Int J Environ Res Public Health, 2020 Mar 03;17(5).
PMID: 32138266 DOI: 10.3390/ijerph17051633

Within last 17 years two widespread epidemics of severe acute respiratory syndrome (SARS) occurred in China, which were caused by related coronaviruses (CoVs): SARS-CoV and SARS-CoV-2. Although the origin(s) of these viruses are still unknown and their occurrences in nature are mysterious, some general patterns of their pathogenesis and epidemics are noticeable. Both viruses utilize the same receptor-angiotensin-converting enzyme 2 (ACE2)-for invading human bodies. Both epidemics occurred in cold dry winter seasons celebrated with major holidays, and started in regions where dietary consumption of wildlife is a fashion. Thus, if bats were the natural hosts of SARS-CoVs, cold temperature and low humidity in these times might provide conducive environmental conditions for prolonged viral survival in these regions concentrated with bats. The widespread existence of these bat-carried or -released viruses might have an easier time in breaking through human defenses when harsh winter makes human bodies more vulnerable. Once succeeding in making some initial human infections, spreading of the disease was made convenient with increased social gathering and holiday travel. These natural and social factors influenced the general progression and trajectory of the SARS epidemiology. However, some unique factors might also contribute to the origination of SARS in Wuhan. These factors are discussed in different scenarios in order to promote more research for achieving final validation.

Matched MeSH terms: Zoonoses
Nine cases of human dipylidiasis in Moscow region during 1987 to 2017

Bronstein AM, Fedyanina LV, Maximova MS, Lukashev AN, Sergeev AR

Trop Biomed, 2020 Mar 01;37(1):194-200.
PMID: 33612730

Dipylidium caninum is a parasite that commonly infects dogs and cats worldwide. The large population of wild and stray dogs and cats may potentially transmit D. caninum to humans via their flea and lice. Humans are an accidental host, and dipylidiasis is more commonly seen in infants and children. There is scant information about human dipylidiasis in Russia. We report nine cases of dipylidiasis - eight in children and one in an adult. The patients were asymptomatic, except for excreting active proglottids in their faeces, which was the most common complaint. The clinical significance of asymptomatic dipylidiasis is not understood, except mothers were anxious because of the continuous appearance of active worms in the faeces of their children. The patients were successfully treated with praziquantel (15 mg/kg). Preventing dipylidiasis in pets and humans requires the control of fleas and lice, avoiding the outdoor defecation of definitive hosts, deworming pets, preventing children from playing with stray animals and spread of information about dipylidiasis among pet owners. Dogs and cats in many places in Russia breed freely, defecate outdoors in any area, and are not subjected to deworming and insect control. These circumstances favour the fact that, although this zoonosis is rare, it is a re-emerging disease and might reach important levels in Russia.

Matched MeSH terms: Zoonoses/epidemiology*; Zoonoses/parasitology
Fulltext Leptospira interrogans and Leptospira kirschneri are the dominant Leptospira species causing human leptospirosis in Central Malaysia

Philip N, Bahtiar Affendy N, Ramli SNA, Arif M, Raja P, Nagandran E, et al.

PLoS Negl Trop Dis, 2020 Mar;14(3):e0008197.
PMID: 32203511 DOI: 10.1371/journal.pntd.0008197

BACKGROUND: Leptospirosis, commonly known as rat-urine disease, is a global but endemic zoonotic disease in the tropics. Despite the historical report of leptospirosis in Malaysia, the information on human-infecting species is limited. Determining the circulating species is important to understand its epidemiology, thereby to strategize appropriate control measures through public health interventions, diagnostics, therapeutics and vaccine development.
METHODOLOGY/PRINCIPLE FINDINGS: We investigated the human-infecting Leptospira species in blood and serum samples collected from clinically suspected leptospirosis patients admitted to three tertiary care hospitals in Malaysia. From a total of 165 patients, 92 (56%) were confirmed cases of leptospirosis through Microscopic Agglutination Test (MAT) (n = 43; 47%), Polymerase Chain Reaction (PCR) (n = 63; 68%) or both MAT and PCR (n = 14; 15%). The infecting Leptospira spp., determined by partial 16S rDNA (rrs) gene sequencing revealed two pathogenic species namely Leptospira interrogans (n = 44, 70%) and Leptospira kirschneri (n = 17, 27%) and one intermediate species Leptospira wolffii (n = 2, 3%). Multilocus sequence typing (MLST) identified an isolate of L. interrogans as a novel sequence type (ST 265), suggesting that this human-infecting strain has a unique genetic profile different from similar species isolated from rodents so far.
CONCLUSIONS/SIGNIFICANCE: Leptospira interrogans and Leptospira kirschneri were identified as the dominant Leptospira species causing human leptospirosis in Central Malaysia. The existence of novel clinically important ST 265 (infecting human), that is different from rodent L. interrogans strains cautions reservoir(s) of these Leptospira lineages are yet to be identified.

Matched MeSH terms: Zoonoses
Fulltext Description, molecular characteristics and Wolbachia endosymbionts of Onchocerca borneensis Uni, Mat Udin & Takaoka n. sp. (Nematoda: Filarioidea) from the Bornean bearded pig Sus barbatus Müller (Cetartiodactyla: Suidae) of Sarawak, Malaysia

Uni S, Mat Udin AS, Agatsuma T, Junker K, Saijuntha W, Bunchom N, et al.

Parasit Vectors, 2020 Feb 06;13(1):50.
PMID: 32028994 DOI: 10.1186/s13071-020-3907-8

BACKGROUND: The genus Onchocerca Diesing, 1841 includes species of medical importance, such as O. volvulus (Leuckart, 1893), which causes river blindness in the tropics. Recently, zoonotic onchocercosis has been reported in humans worldwide. In Japan, O. dewittei japonica Uni, Bain & Takaoka, 2001 from wild boars is a causative agent for this zoonosis. Many filarioid nematodes are infected with Wolbachia endosymbionts which exhibit various evolutionary relationships with their hosts. While investigating the filarial fauna of Borneo, we discovered an undescribed Onchocerca species in the bearded pig Sus barbatus Müller (Cetartiodactyla: Suidae).
METHODS: We isolated Onchocerca specimens from bearded pigs and examined their morphology. For comparative material, we collected fresh specimens of O. d. dewittei Bain, Ramachandran, Petter & Mak, 1977 from banded pigs (S. scrofa vittatus Boie) in Peninsular Malaysia. Partial sequences of three different genes (two mitochondrial genes, cox1 and 12S rRNA, and one nuclear ITS region) of these filarioids were analysed. By multi-locus sequence analyses based on six genes (16S rDNA, ftsZ, dnaA, coxA, fbpA and gatB) of Wolbachia, we determined the supergroups in the specimens from bearded pigs and those of O. d. dewittei.
RESULTS: Onchocerca borneensis Uni, Mat Udin & Takaoka n. sp. is described on the basis of morphological characteristics and its genetic divergence from congeners. Molecular characteristics of the new species revealed its close evolutionary relationship with O. d. dewittei. Calculated p-distance for the cox1 gene sequences between O. borneensis n. sp. and O. d. dewittei was 5.9%, while that between O. d. dewittei and O. d. japonica was 7.6%. No intraspecific genetic variation was found for the new species. Wolbachia strains identified in the new species and O. d. dewittei belonged to supergroup C and are closely related.
CONCLUSIONS: Our molecular analyses of filarioids from Asian suids indicate that the new species is sister to O. d. dewittei. On the basis of its morphological and molecular characteristics, we propose to elevate O. d. japonica to species level as O. japonica Uni, Bain & Takaoka, 2001. Coevolutionary relationships exist between the Wolbachia strains and their filarial hosts in Borneo and Peninsular Malaysia.

Matched MeSH terms: Zoonoses/transmission
An overview of rickettsiae in Southeast Asia: Vector-animal-human interface

Low VL, Tan TK, Khoo JJ, Lim FS, AbuBakar S

Acta Trop, 2020 Feb;202:105282.
PMID: 31778642 DOI: 10.1016/j.actatropica.2019.105282

Rickettsioses are emerging, and re-emerging diseases caused by obligate intracellular arthropod-borne bacteria that infect humans and animals worldwide. Various rickettsiae such as Orientia, Rickettsia, Anaplasma and Ehrlichia have been circulated in companion, domesticated and wild animals through bites of infected ticks, fleas, lice or mites. This review summarizes the infections of rickettsiae, including the newly discovered regional species Rickettsia thailandii, Candidatus Rickettsia sepangensis, Candidatus Rickettsia johorensis, Candidatus Rickettsia laoensis, Candidatus Rickettsia mahosotii, Candidatus Rickettsia khammouanensis, Candidatus Anaplasma pangolinii, and other novel genotypes in vectors, humans and animals in Southeast Asia. Issues on some unidentified rickettsiae that elicit immune responses and production of antibodies that are cross-reactive with the antigens used are discussed. Knowledge gaps which required attention are also identified in this review.

Matched MeSH terms: Zoonoses
Immune responses in mice and pigs after oral vaccination with rabies virus vectored Nipah disease vaccines

Shuai L, Ge J, Wen Z, Wang J, Wang X, Bu Z

Vet Microbiol, 2020 Feb;241:108549.
PMID: 31928698 DOI: 10.1016/j.vetmic.2019.108549

Nipah virus (NiV) is a re-emerging zoonotic pathogen that causes high mortality in humans and pigs. Oral immunization in free-roaming animals is one of the most practical approaches to prevent NiV pandemics. We previously generated a recombinant rabies viruses (RABV) Evelyn-Rokitnicki-Abelseth (ERA) strain, rERAG333E, which contains a mutation from arginine to glutamic acid at residue 333 of glycoprotein (G333E) and serves as an oral vaccine for dog rabies. In this study, we generated two recombinant RABVs, rERAG333E/NiVG and rERAG333E/NiVF, expressing the NiV Malaysian strain attachment glycoprotein (NiV-G) or fusion glycoprotein (NiV-F) gene based on the rERAG333E vector platform. Both rERAG333E/NiVG and rERAG333E/NiVF displayed growth properties similar to those of rERAG333E and caused marked syncytia formation after co-infection in BSR cell culture. Adult and suckling mice intracerebrally inoculated with the recombinant RABVs showed NiV-G and NiV-F expression did not increase the virulence of rERAG333E. Oral vaccination with rERAG333E/NiVG either singularly or combined with rERAG333E/NiVF induced significant NiV neutralizing antibody against NiV and RABV, and IgG to NiV-G or NiV-F in mice and pigs. rERAG333E/NiVG and rERAG333E/NiVF thus appeared to be suitable candidates for further oral vaccines for potential animal targets in endemic areas of NiV disease and rabies.

Matched MeSH terms: Zoonoses
Leptospirosis: Increasing importance in developing countries

Soo ZMP, Khan NA, Siddiqui R

Acta Trop, 2020 Jan;201:105183.
PMID: 31542372 DOI: 10.1016/j.actatropica.2019.105183

Leptospirosis is a zoonotic disease caused by the pathogenic helical spirochetes, Leptospira. Symptoms include sudden-onset fever, severe headaches, muscle pain, nausea and chills. Leptospirosis is endemic in developing countries such as Malaysia, India, Sri Lanka, and Brazil where thousands of cases are reported annually. The disease risk factors include the high population of reservoirs, environmental factors, recreational factors, and occupational factors. To end the endemicity of leptospirosis, these factors need to be tackled. The management of leptospirosis needs to be refined. Early diagnosis remains a challenge due to a lack of clinical suspicion among physicians, its non-specific symptoms and a limited availability of rapid point-of-care diagnostic tests. The purpose of this review is to provide insight into the status of leptospirosis in developing countries focusing on the risk factors and to propose methods for the improved management of the disease.

Matched MeSH terms: Zoonoses
The Effects of Amplification and Dilution Agent in Transmitting Sin Nombre Virus (SNV) in Deer Mouse Population

Lloyd Wen Feng Lee, Mohd Hafiz Mohd

MATEMATIKA, 2020;36(2):85-98.
MyJurnal

1Malaysia
2 (UKM)43600 Bangi, Selangor, Malaysia
∗Corresponding author:

Numerous studies have linked biodiversity with zoonotic disease control. However, researchers have warned against simply believing that the increase in biodiversity can reduce the infection disease in the community. They proposed that amplification effect (increase in biodiversity accompanied by an increase in disease prevalence) might sometimes occur. Thus, we formulated a deterministic model to consider the impact of an amplification or dilution agent on the SNV transmission in the deer mouse population. Bifurcation analysis was carried out to examine the combined influences of the environmental carrying capacity, the interspecific competition strength and the impact of amplification or dilution agent on the deer mouse population. Our results showed that the system with amplification agent required a higher carrying capacity or stronger interspecific strength to compensate for its amplification effect in suppressing the SNV prevalence; this situation explains the lack of reduction in SNV prevalence despite the presence of high biodiversity in some empirical studies. In this study, we highlight the importance of investigating the roles of the additional species in an assemblage to better understand their relationship with the SNV prevalence in deer mouse population.

Matched MeSH terms: Zoonoses
Fulltext Current and future trends in socio-economic, demographic and governance factors affecting global primate conservation

Estrada A, Garber PA, Chaudhary A

PeerJ, 2020;8:e9816.
PMID: 32884865 DOI: 10.7717/peerj.9816

Currently, ~65% of extant primate species (ca 512 species) distributed in 91 countries in the Neotropics, mainland Africa, Madagascar, South Asia and Southeast Asia are threatened with extinction and 75% have declining populations as a result of deforestation and habitat loss resulting from increasing global market demands, and land conversion for industrial agriculture, cattle production and natural resource extraction. Other pressures that negatively impact primates are unsustainable bushmeat hunting, the illegal trade of primates as pets and as body parts, expanding road networks in previously isolated areas, zoonotic disease transmission and climate change. Here we examine current and future trends in several socio-economic factors directly or indirectly affecting primates to further our understanding of the interdependent relationship between human well-being, sustainable development, and primate population persistence. We found that between 2001 and 2018 ca 191 Mha of tropical forest (30% canopy cover) were lost as a result of human activities in the five primate range regions. Forty-six percent of this loss was in the Neotropics (Mexico, Central and South America), 30% in Southeast Asia, 21% in mainland Africa, 2% in Madagascar and 1% in South Asia. Countries with the greatest losses (ca 57% of total tree cover loss) were Brazil, Indonesia, DRC, China, and Malaysia. Together these countries harbor almost 50% of all extant primate species. In 2018, the world human population was estimated at ca 8bn people, ca 60% of which were found in primate range countries. Projections to 2050 and to 2100 indicate continued rapid growth of the human populations in these five primate range regions, with Africa surpassing all the other regions and totaling ca 4bn people by the year 2100. Socioeconomic indicators show that, compared to developed nations, most primate range countries are characterized by high levels of poverty and income inequality, low human development, low food security, high levels of corruption and weak governance. Models of Shared Socioeconomic Pathway scenarios (SSPs) projected to 2050 and 2100 showed that whereas practices of increasing inequality (SSP4) or unconstrained growth in economic output and energy use (SSP5) are projected to have dire consequences for human well-being and primate survivorship, practices of sustainability-focused growth and equality (SSP1) are expected to have a positive effect on maintaining biodiversity, protecting environments, and improving the human condition. These results stress that improving the well-being, health, and security of the current and future human populations in primate range countries are of paramount importance if we are to move forward with effective policies to protect the world's primate species and promote biodiversity conservation.

Matched MeSH terms: Zoonoses
The Role of Ecological Linkage Mechanisms in Plasmodium knowlesi Transmission and Spread

Davidson G, Chua TH, Cook A, Speldewinde P, Weinstein P

Ecohealth, 2019 12;16(4):594-610.
PMID: 30675676 DOI: 10.1007/s10393-019-01395-6

Defining the linkages between landscape change, disease ecology and human health is essential to explain and predict the emergence of Plasmodium knowlesi malaria, a zoonotic parasite residing in Southeast Asian macaques, and transmitted by species of Anopheles mosquitos. Changing patterns of land use throughout Southeast Asia, particularly deforestation, are suggested to be the primary drivers behind the recent spread of this zoonotic parasite in humans. Local ecological changes at the landscape scale appear to be increasing the risk of disease in humans by altering the dynamics of transmission between the parasite and its primary hosts. This paper will focus on the emergence of P. knowlesi in humans in Malaysian Borneo and the ecological linkage mechanisms suggested to be playing an important role.

Matched MeSH terms: Zoonoses/epidemiology; Zoonoses/transmission*
Fulltext Long-Tailed Macaque Response to Deforestation in a Plasmodium knowlesi-Endemic Area

Stark DJ, Fornace KM, Brock PM, Abidin TR, Gilhooly L, Jalius C, et al.

Ecohealth, 2019 12;16(4):638-646.
PMID: 30927165 DOI: 10.1007/s10393-019-01403-9

Land-use changes can impact infectious disease transmission by increasing spatial overlap between people and wildlife disease reservoirs. In Malaysian Borneo, increases in human infections by the zoonotic malaria Plasmodium knowlesi are hypothesised to be due to increasing contact between people and macaques due to deforestation. To explore how macaque responses to environmental change impact disease risks, we analysed movement of a GPS-collared long-tailed macaque in a knowlesi-endemic area in Sabah, Malaysia, during a deforestation event. Land-cover maps were derived from satellite-based and aerial remote sensing data and models of macaque occurrence were developed to evaluate how macaque habitat use was influenced by land-use change. During deforestation, changes were observed in macaque troop home range size, movement speeds and use of different habitat types. Results of models were consistent with the hypothesis that macaque ranging behaviour is disturbed by deforestation events but begins to equilibrate after seeking and occupying a new habitat, potentially impacting human disease risks. Further research is required to explore how these changes in macaque movement affect knowlesi epidemiology on a wider spatial scale.

Matched MeSH terms: Zoonoses/epidemiology*
Fulltext Natural Human Infections With Plasmodium cynomolgi and Other Malaria Species in an Elimination Setting in Sabah, Malaysia

Grignard L, Shah S, Chua TH, William T, Drakeley CJ, Fornace KM

J Infect Dis, 2019 11 06;220(12):1946-1949.
PMID: 31418017 DOI: 10.1093/infdis/jiz397

To determine the presence and species composition of malaria infections, we screened a subset of samples collected during a cross-sectional survey in Northern Sabah, Malaysia using highly sensitive molecular techniques. Results identified 54 asymptomatic submicroscopic malaria infections, including a large cluster of Plasmodium falciparum and 3 P. knowlesi infections. We additionally identified 2 monoinfections with the zoonotic malaria Plasmodium cynomolgi, both in individuals reporting no history of forest activities or contact with macaques. Results highlight the need for improved surveillance strategies to detect these infections and determine public health impacts.

Matched MeSH terms: Zoonoses

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