1.Prevalence and risk factors of Toxoplasma infection – an update in Malaysian pregnant women
Chemoh, W. ; Nur Farhana, M.N. ; Noor Azmi, M.A. ; Si Lay, K. ; Sawangjaroen, N. ; Tan, T.C. ; Chandramathi, S.R ; Nissapatorn, V.
Tropical Biomedicine 2019;36(3):694-702
Toxoplasma gondii is a protozoan parasite that is capable of causing a zoonotic
disease, known as toxoplasmosis. Vertical transmission of T. gondii from the mother to the
fetus, during pregnancy may cause severe complications to the developing fetus. This current
study aimed to determine the seroprevalence and investigate the associated risk factors of
Toxoplasma infection in pregnant women (n=219) visiting the antenatal clinic at UMMC.
While the elevated level of anti-Toxoplasma IgG and IgM antibodies indicates the presence
of infection, it fails to differentiate between a past and a recent infection. Thus, the study
also demonstrates the usefulness of IgG avidity in validating the timing of infection. The
serum samples were tested for the presence of anti-Toxoplasma IgG and IgM antibodies by
ELISA test, and the seropositive samples for both anti-Toxoplasma IgG and IgM antibodies
were further evaluated by IgG avidity. The results showed that the overall prevalence of T.
gondii seropositivity was 34.7%. Of these, 30.6% (67/219) were positive for anti-Toxoplasma
IgG antibody only, 2.3% (5/219) were positive for anti-Toxoplasma IgM only, and the remaining
1.8% (4/219) was positive for both anti-Toxoplasma IgG and IgM antibodies. All of the pregnant
women who were positive for both anti-Toxoplasma IgG and IgM antibody were found to
have past infection when evaluated by IgG avidity. In this study, Malay ethnicity and the
number of existing previous children were significantly associated with T. gondii seropositivity
(p<0.05). Based on these findings, information and education on the transmission and
prevention of congenital toxoplasmosis are very crucial as a public health effort towards a
healthier society.
2.DNA barcoding relates Trichuris species from a human and a man’s best friend to non-human primate sources
Brandon-Mong, G.J. ; Ketzis, J.K. ; Choy, J.S. ; Boonroumkaew, P. ; Tooba, M. ; Sawangjaroen, N. ; Yasiri, A ; Janwan, P. ; Tan, T.C. ; Nissapatorn, V.
Tropical Biomedicine 2018;35(4):1131-1139
Trichuris trichiura, the whipworm of humans, is one of the most prevalent soiltransmitted
helminths (STH) reported worldwide. According to a recent study, out of 289
STH studies in Southeast Asia, only three studies used molecular methods. Hence, the
genetic assemblages of Trichuris in Southeast Asia are poorly understood. In this study,
we used partial mitochondrial DNA (cytochrome c oxidase subunit 1 or COI) sequences for
analysis. Trichuris grouped in a same clade with different hosts indicate the potential of
cross infection between hosts. Based on COI, the adult Trichuris isolated from a Malaysian
patient was most closely related to Trichuris isolated from Papio anubis (olive baboons)
from the USA. The Trichuris isolated from the dog from Malaysia was genetically similar
to a Trichuris species isolated from Macaca silenus (lion-tailed macaque) from Czech
Republic. Both the human and dog isolated Trichuris grouped in clades with different
hosts indicating the potential of cross infection between hosts. Specific PCR primers
based on the partial COI of T. trichiura isolated from African green monkey and T. serrata
were designed and successfully amplified using multiplex PCR of the pooled DNA samples.
Our results suggest a complex parasite-host relationship, and support the theory of cross
infection of Trichuris between humans and non-human primates as suggested in previous
publications.