Banner Image for Directory


Ian Hewitt Mendenhall

Adjunct Assistant Professor


Ian H Mendenhall was awarded his B.S. in Entomology and Zoology from the University of Wisconsin at Madison and then worked as the laboratory supervisor at Clarke Mosquito Control where he directed arbovirus surveillance in mosquitoes and birds in the greater Chicagoland area from 2000-2003. He then attended the Tulane School of Public Health and Tropical Medicine where he was awarded a Ph.D. in Parasitology with a focus in Vector Borne Infectious Diseases and was a Fulbright Scholar for his dissertation research in Colombia.

In 2010, Ian joined the Programme in Emerging Infectious Diseases at Duke-NUS Medical School in Singapore as a Research Fellow. He is currently a Principal Research Scientist in the Laboratory of Virus Evolution run by Dr. Gavin Smith. His research interests focus on the ecology, evolution, and epidemiology of infectious diseases, specifically zoonotic pathogens and arthropod borne parasites. He was awarded a New Investigator grant to develop methods to more efficaciously detect bat borne viruses. Ian works or has worked in Singapore, Vietnam, Indonesia, Kazakhstan, India and Cambodia with government and university labs to build capacity and better inform biosurveillance.

I am interested in improving surveillance for zoonotic and arthropod-borne pathogens by understanding the interactions of the host, vector, pathogen and environment. We study zoonotic pathogens in small mammals and bats to better understand and characterize the factors that govern risk and spillover. We conduct surveillance, use PCR, multiplex serology and develop tools for isolation combined with phylogenetic and GIS analyses.

Research Projects

1. Investigating the risk of human disease from small mammals and bats

This is a five year project in Cambodia to study the risk of pathogen spillover from bats and small mammals into humans. Viral and bacterial transmission patterns often vary, making detection difficult, and resulting in expensive and often inefficient surveillance. Our objective is to generate probabilistic distribution maps for small mammals and bats and viral and bacterial communities using randomly selected points stratified across different provinces and habitats. We are also sampling bats, small mammals and humans working at high-risk interfaces and screening them for several different viruses and bacteria, in addition to evidence of exposure through serology.

2. Bat harvesting in India: Detection, characterization, and mitigation of risk

Bats are increasingly recognized as important reservoirs of zoonotic viruses. Consumption of wildlife is endemic across Asia and bats are frequently killed for protein and medicinal purposes. Our study in India focuses on the risk of bat borne virus spillover into human populations who hunt and consume bats. By studying both bats and humans at this high risk interface with genomic and serologic detection, we can characterize the zoonotic agents and better understand the dynamics of cross-species transmission.

3. Zooprophylaxis Aided Ivermectin-based Vector Elimination (ZAIVE): A Novel Approach for Vector Control within Hotspots and for Reactive Case Response

Malaria remains an important contributor to morbidity and mortality. While many countries in Southeast Asia have made important strides towards elimination, some interventions like ITNs have had limited effectiveness due to outdoor biting vectors. Addressing this gap is critical for continued progress. Ivermectin has emerged as a potential new tool towards malaria elimination. Zooprophylaxis involves using large herd mammals as bait to ‘pull’ vectors into traps, providing passive protection. In this study we are looking at the impact of ivermectin on two important malaria vectors (An. dirus and An. epiroticus) with cow feeding studies and the impact of mass ivermectin treatment of cows on Anopheles populations in the Central Highlands.

4. Sero-survey of Nipah virus and other pathogenic bat borne paramyxoviruses in Cambodia

Bat borne paramyxoviruses, such as Nipah virus (NiV) and Hendra virus (HeV) are considered select agents. NiV is endemic across SE Asia, with recent outbreaks in Bangladesh and India. In Cambodia, NiV has been isolated and detected from two species of flying foxes. Human infections have not been reported in Cambodia and the potential spillover risk remains unknown. We use a multiplex binding assay with glycoproteins from henipaviruses to detect IgG in sera from convalescent patients to detect exposure.

Koh J, Itahana, Mendenhall IH, Low DHW, Chionh YT, Wang LF, Itahana Koji. Uniquely high and broad ABCB1 expression protects bats from DNA damage. Nature Communications. 2019. In press.

Mendenhall IH, Borthwick S, Sena Neves E, Low D, Jayajumar J, Gunalan V, Maurer-Stroh S, Smith G. Comparative metaviromic analysis of the feces and urine of the Cave Nectar Bat (Eonycteris spelaea). Viruses. 2019. 11(3), 250;

Mendenhall IH, Kerimbayev AA, Strochkov VM, Sultankulova KT, Kopeyev SK, Su YCF, Smith GJD, Orynbayev MB. Discovery and characterization of novel bat coronavirus lineages from Kazakhstan. Viruses. 2019. In press.

Anderson DE, Islam A, Crameri G, Todd S, Islam A, Khan SU, Foord A, Rahman MZ, Mendenhall IH, Luby SP, Gurley ES, Daszak P, Epstein JH, Wang LF. Isolation and Full-Genome Characterization of Nipah Viruses from Bats, Bangladesh. Emerging infectious diseases. 2019, 25(1), 166-170.

Wen M, Ng JHJ, Chionh YT, Chia WN, Mendenhall IH, Lee BYH, Irving AT, LF Wang. Exploring the genome and transcriptome of the cave nectar bat Eonycteris spelaea with PacBio long-read sequencing. GigaScience. 2018. giy116,

Laing ED*, Mendenhall IH*, Linster M, Low DHW, Chen Y, Yan L, Sterling SL, Borthwick S, Neves ES, Lim JSL, Skiles M, Lee BPY, Wang LF, Broder CC, Smith GJD. Serologic evidence of exposure to filoviruses in fruit bats, Singapore. Emerging Infectious Diseases. 2018 Jan.

Mendenhall IH, Ch’ng L, Sena-Neves E, Borthwick S, Smith GJD. High diversity of medically-important gastrointestinal rodent-borne helminths in Singapore. Zoonoses and Public Health. 2017 Dec 19. https://doi:10.1111/zph.12438.

Mendenhall IH, Skiles M, Sena Neves E, Borthwick, Low D, Liang B, Lee B P Y-H, D, Su Y, Smith G. Influence of age and body condition on astrovirus infection of bats in Singapore: An evolutionary and epidemiological analysis. One Health. 2017 Oct 6;4:27-33. doi: 10.1016/j.onehlt.2017.10.001.

Mendenhall IH, Manuel M, Moorthy M, Lee TTM, Low DHW, Misse D, Gubler D, Ellis BR, Ooi EE, Pompon J (2017). Aedes peridomestic vector species are competent in transmitting arboviruses in cities. PLoS Neglected Tropical Diseases.

Mendenhall IH, Borthwick S, Sena Neves E, Low D, Linster M, Liang B, Skiles M, Jayajumar J, Han H, Gunalan V, Lee B P Y-H, Okahara K, Wang L, Maurer-Stroh S, Su Y, Smith G (2016). Identification of a lineage D betacoronavirus in cave nectar bats (Eonycteris spelaea) in Singapore and an overview of lineage D reservoir ecology in SE Asian bats. Transboundary and Emerging Diseases. doi:10.1111/tbed.12568

Mendenhall IH, Low D, Sena Neves E, Anwar A, Oh S, Su Y, Smith G (2016). Evidence of canine parvovirus transmission to a civet cat (Paradoxurus musangus) in Singapore. One Health. 2, December 2016, 122-125.

Zhou P, Tachedjian M, Wynne JW, Boyd V, Cui J, Smith I, Cowled C, Ng JH, Mok L, Michalski WP, Mendenhall IH, Tachedijian, Wang L, Baker M (2016): Contraction of the type I IFN locus and unusual constitutive expression of IFN-alpha in bats. Proceedings of the National Academy of Sciences of the United States of America. 113:10 doi: 10.1073/pnas.1518240113.

Fair JM, Stokes MM, Pennington D, Mendenhall IH (2016). Scientific collaborations: How do we measure the return on relationships? Frontiers in Public Health. 4:9 doi:10.3389/fpubh.2016.00009.

Mendenhall IH, Smith GDJ, Vijaykrishna D (2015). Ecological drivers of virus evolution: Astrovirus as a case study.  Journal of Virology. JVI.02971-14.

Bahl J, Krauss S, Kühnert D, Fourment M, Raven G, Pryor S, Niles L, Danner A, Walker D, Mendenhall IH, Su Y, Dugan V, Halpin R, Stockwell T, Webby R, Wentworth D, Drummond A, Smith G, Webster R (2013). Long-term spatial diffusion patterns of avian influenza A virus is independent of migratory flyways. PLoS Pathogens 9(8): e1003570. Doi:10.1371/journal.ppat.1003570.

Mendenhall IH, Tello SA, Neira LA, Castillo LF, Ocampo CB, Wesson DM (2012). Host preference of the arbovirus vector Culex erraticus at Sonso Lake, Cauca Valley Department, Colombia. Journal of Medical Entomology. 49(5):1092-1102.

Foppa IM, Beard RH, Mendenhall IH. The impact of West Nile virus on the abundance of North American birds (2011). BMC Veterinary Research. 11;7:43.