Yvonne Lim

Prof. Yvonne Lim

orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 May 2014 in PLOS Neglected Tropical Diseases
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Journal Article
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SLSoo Ching Lee
Soo Ching Lee
MTMei San Tang
Mei San Tang
YLYvonne Lim
Yvonne Lim
SCSeow Huey Choy
Seow Huey Choy
ZKZachary D. Kurtz
Zachary D. Kurtz
PLP'Ng Loke
P'Ng Loke
Soil-transmitted helminths colonize more than 1.5 billion people worldwide, yet little is known about how they interact with bacterial communities in the gut microbiota. Differences in the gut microbiota between individuals living in developed and developing countries may be partly due to the presence of helminths, since they predominantly infect individuals from developing countries, such as the indigenous communities in Malaysia we examine in this work. We compared the composition and diversity of bacterial communities from the fecal microbiota of 51 people from two villages in Malaysia, of which 36 (70.6%) were infected by helminths. The 16S rRNA V4 region was sequenced at an average of nineteen thousand sequences per samples. Helminth-colonized individuals had greater species richness and number of observed OTUs with enrichment of Paraprevotellaceae, especially with Trichuris infection. We developed a new approach of combining centered log-ratio (clr) transformation for OTU relative abundances with sparse Partial Least Squares Discriminant Analysis (sPLS-DA) to enable more robust predictions of OTU interrelationships. These results suggest that helminths may have an impact on the diversity, bacterial community structure and function of the gut microbiota. Soil-transmitted helminths are carried by large numbers of people in developing countries. These parasites live in the gut and may interact with bacterial communities in the gut, also called the gut microbiota. To determine whether there are alterations to the gut microbiota that are associated with helminth infections, we examined the types of bacteria present in fecal samples from rural Malaysians, many of whom are helminth-positive and find it likely that helminth colonization alters the gut microbiota for rural Malaysians.

29 April 2016 in Science
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Journal Article
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DRDeepshika Ramanan
Deepshika Ramanan
RBRowann Bowcutt
Rowann Bowcutt
SLSoo Ching Lee
Soo Ching Lee
MTMei San Tang
Mei San Tang
ZKZachary D. Kurtz
Zachary D. Kurtz
KCKen Cadwell
Ken Cadwell
Parasitic worms affect gut microbes: Improved hygiene practices in high-income countries may come with an increased risk of developing inflammatory bowel disease (IBD) or other similar disorders. Ramanan et al. show that intestinal helminth infection, caused by parasitic worms, protects IBD-susceptible mice from developing the disease. The infection increases specific protective species and limits other inflammatory members of the microbiota. People from helminth-endemic regions harbored a similar protective microbiota, and their deworming led to an increase in inflammatory Bacteroidales species, similar to what the authors observed in the mice. Thus, a changing microbial environment may shape susceptibility to inflammatory disease. Science , this issue p. 608

1 March 2011 in PLOS Neglected Tropical Diseases
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RNRomano Ngui
Romano Ngui
SISaidon Ishak
Saidon Ishak
CCChow Sek Chuen
Chow Sek Chuen
RMRohela Mahmud
Rohela Mahmud
YLYvonne Lim
Yvonne Lim
Intestinal parasitic infections (IPIs) have a worldwide distribution and have been identified as one of the most significant causes of illnesses and diseases among the disadvantaged population. In Malaysia, IPIs still persist in some rural areas, and this study was conducted to determine the current epidemiological status and to identify risk factors associated with IPIs among communities residing in rural and remote areas of West Malaysia. A total of 716 participants from 8 villages were involved, comprising those from 1 to 83 years old, 550 (76.8%) participants aged ≤12 years and 166 (23.2%) aged ≥13 years, and 304 (42.5%) male and 412 (57.5%) female. The overall prevalence of IPIs was high (73.2%). Soil-transmitted helminth (STH) infections (73.2%) were significantly more common compared to protozoa infections (21.4%) (p<0.001). The prevalence of IPIs showed an age dependency relationship, with significantly higher rates observed among those aged ≤12 years. Multivariate analysis demonstrated that participants aged ≤12 years (OR = 2.23; 95% CI = 1.45–3.45), low household income (OR = 4.93; 95% CI = 3.15–7.73), using untreated water supply (OR = 2.08; 95% CI = 1.36–3.21), and indiscriminate defecation (OR = 5.01; 95% CI = 3.30–7.62) were identified as significant predictors of IPIs among these communities. Essentially, these findings highlighted that IPIs are highly prevalent among the poor rural communities in West Malaysia. Poverty and low socioeconomic with poor environmental sanitation were indicated as important predictors of IPIs. Effective poverty reduction programmes, promotion of deworming, and mass campaigns to heighten awareness on health and hygiene are urgently needed to reduce IPIs. Intestinal parasitic infections (IPIs) are among the most prevalent human afflictions; these infections still have major impact on the socioeconomic and public health of the bottom billion of the world's poorest people. Although Malaysia has a thriving economy, IPIs are still very much prevalent and causing major health problems among the poor and in deprived communities especially in rural and remote areas. A comprehensive study is paramount to determine the current prevalent and factors closely linked to IPIs so that effective control measures can be instituted. In view of this, we conducted this study to provide detailed data of the existing status of IPIs among 716 participants living in rural and remote areas in Peninsular Malaysia. The establishment of such data is beneficial for the public health service to justify and facilitate the reassessment of control strategies and policies in terms of reducing intestinal parasitism. With effective control measures in place, these communities (especially children) will have a greater opportunity for a better future in terms of health and educational achievement and eventually will be at par socially and economically with urban communities in Malaysia.

24 June 2015 in Parasites & Vectors
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VLVan Lun Low
Van Lun Low
STST Tay
ST Tay
KKKai Ling Kho
Kai Ling Kho
FKFui Xian Koh
Fui Xian Koh
TTTiong Kai Tan
Tiong Kai Tan
MSMohd Sofian-Azirun
Mohd Sofian-Azirun
The morphotaxonomy of Rhipicephalus microplus complex has been challenged in the last few years and prompted many biologists to adopt a DNA-based method for distinguishing the members of this group. In the present study, we used a mitochondrial DNA analysis to characterise the genetic assemblages, population structure and dispersal pattern of R. microplus from Southeast Asia, the region where the species originated. A phylogeographic analysis inferred from the 16S rRNA and cytochrome oxidase subunit I (COI) genes was performed with five populations of R. microplus collected from cattle in Malaysia. Malaysian R. microplus sequences were compared with existing COI and 16S rRNA haplotypes reported globally in NCBI GenBank. A total of seven and 12 unique haplotypes were recovered by the 16S rRNA and COI genes, respectively. The concatenated sequences of both 16S rRNA and COI revealed 18 haplotypes. Haplotype network and phylogenetic analyses based on COI+16S rRNA sequences revealed four genetically divergent groups among Malaysian R. microplus. The significantly low genetic differentiation and high gene flow among Malaysian R. microplus populations supports the occurrence of genetic admixture. In a broader context, the 16S rRNA phylogenetic tree assigned all isolates of Malaysian R. microplus into the previously described African/the Americas assemblage. However, the COI phylogenetic tree provides higher resolution of R. microplus with the identification of three main assemblages: clade A sensu Burger et al. (2014) comprises ticks from Southeast Asia, the Americas and China; clade B sensu Burger et al. (2014) is restricted to ticks that originated from China; and clade C sensu Low et al. (2015) is a new genetic assemblage discovered in this study comprising ticks from India and Malaysia. We conclude that the R. microplus complex consisting of at least five taxa: R. australis, R. annulatus, R. microplus clade A sensu Burger et al. (2014), R. microplus clade B sensu Burger et al. (2014) and the new taxon, R. microplus clade C sensu Low et al. (2015). The use of COI as the standard genetic marker in discerning the genetic assemblages of R. microplus from a broad range of biogeographical regions is proposed.

22 August 2013 in PLOS Neglected Tropical Diseases
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HSHany Sady
Hany Sady
Hesham M. Al-MekhlafiHesham M. Al-Mekhlafi
Hesham M. Al-Mekhlafi
MMMohammed A. K. Mahdy
Mohammed A. K. Mahdy
YLYvonne Lim
Yvonne Lim
RMRohela Mahmud
Rohela Mahmud
JSJohari Surin
Johari Surin
Schistosomiasis, one of the most prevalent neglected tropical diseases, is a life-threatening public health problem in Yemen especially in rural communities. This cross-sectional study aims to determine the prevalence and associated risk factors of schistosomiasis among children in rural Yemen. Urine and faecal samples were collected from 400 children. Urine samples were examined using filtration technique for the presence of Schistosoma haematobium eggs while faecal samples were examined using formalin-ether concentration and Kato Katz techniques for the presence of S. mansoni. Demographic, socioeconomic and environmental information were collected via a validated questionnaire. Overall, 31.8% of the participants were found to be positive for schistosomiasis; 23.8% were infected with S. haematobium and 9.3% were infected with S. mansoni. Moreover, 39.5% of the participants were anaemic whereas 9.5% had hepatosplenomegaly. The prevalence of schistosomiasis was significantly higher among children aged >10 years compared to those aged ≤10 years (P<0.05). Multivariate analysis confirmed that presence of other infected family member (P<0.001), low household monthly income (P = 0.003), using unsafe sources for drinking water (P = 0.003), living nearby stream/spring (P = 0.006) and living nearby pool/pond (P = 0.002) were the key factors significantly associated with schistosomiasis among these children. This study reveals that schistosomiasis is still highly prevalent in Yemen. These findings support an urgent need to start an integrated, targeted and effective schistosomiasis control programme with a mission to move towards the elimination phase. Besides periodic drug distribution, health education and community mobilisation, provision of clean and safe drinking water, introduction of proper sanitation are imperative among these communities in order to curtail the transmission and morbidity caused by schistosomiasis. Screening and treating other infected family members should also be adopted by the public health authorities in combating this infection in these communities. Schistosomiasis remains one of the most serious and prevalent diseases worldwide. Despite intensive control efforts by the government and international bodies, schistosomiasis is the second cause of death, after malaria, in Yemen, with an estimated 3 million cases. We screened 400 children in rural areas of five provinces in Yemen for the presence of schistosomiasis. Overall, 31.8% of the children were found to be positive for schistosomiasis; 23.8% were infected by Schistosoma haematobium, and 9.3% were infected by S. mansoni. The study identified the presence of other family members infected with schistosomiasis, low household monthly income, using unsafe water supply as a source for drinking water, living nearby stream/spring and/or pool/pond as the key factors significantly associated with schistosomiasis in these communities. Innovative and integrated control measures to control this infection should be implemented among this population. Periodic school-based and community-based drug distribution, health education, provision of clean and safe drinking water, introduction of proper sanitation will help to reduce the prevalence and morbidity of schistosomiasis among these communities.

16 April 2015 in PLOS Neglected Tropical Diseases
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PHPeter Hotez
Peter Hotez
MBMaria Bottazzi
Maria Bottazzi
USUlrich Strych
Ulrich Strych
LCLi-Yen Chang
Li-Yen Chang
YLYvonne Lim
Yvonne Lim
SASAZALY ABUBAKAR
SAZALY ABUBAKAR
The ten member states of the Association of Southeast Asian Nations (ASEAN) constitute an economic powerhouse, yet these countries also harbor a mostly hidden burden of poverty and neglected tropical diseases (NTDs). Almost 200 million people live in extreme poverty in ASEAN countries, mostly in the low or lower middle-income countries of Indonesia, the Philippines, Myanmar, Viet Nam, and Cambodia, and many of them are affected by at least one NTD. However, NTDs are prevalent even among upper middle-income ASEAN countries such as Malaysia and Thailand, especially among the indigenous populations. The three major intestinal helminth infections are the most common NTDs; each helminthiasis is associated with approximately 100 million infections in the region. In addition, more than 10 million people suffer from either liver or intestinal fluke infections, as well as schistosomiasis and lymphatic filariasis (LF). Intestinal protozoan infections are widespread, while leishmaniasis has emerged in Thailand, and zoonotic malaria (Plasmodium knowlesi infection) causes severe morbidity in Malaysia. Melioidosis has emerged as an important bacterial NTD, as have selected rickettsial infections, and leptospirosis. Leprosy, yaws, and trachoma are still endemic in focal areas. Almost 70 million cases of dengue fever occur annually in ASEAN countries, such that this arboviral infection is now one of the most common and economically important NTDs in the region. A number of other arboviral and zoonotic viral infections have also emerged, including Japanese encephalitis; tick-borne viral infections; Nipah virus, a zoonosis present in fruit bats; and enterovirus 71 infection. There are urgent needs to expand surveillance activities in ASEAN countries, as well as to ensure mass drug administration is provided to populations at risk for intestinal helminth and fluke infections, LF, trachoma, and yaws. An ASEAN Network for Drugs, Diagnostics, Vaccines, and Traditional Medicines Innovation provides a policy framework for the development of new control and elimination tools. Together with prominent research institutions and universities, the World Health Organization (WHO), and its regional offices, these organizations could implement important public health improvements through NTD control and elimination in the coming decade.