Tropical Biomedicine

Antibody cross-reactivity among flaviviruses is a major limitation in understanding the prevalence without vector control measures. In this study, we investigated the presence of Zika virus (ZIKV)-specific antibodies and the significance of their cross-reactivity with other flaviviruses, which could affect the serological specificity in both symptomatic and asymptomatic pregnant women. Among the results obtained from 217 serum samples tested for ZIKV-specific IgM and IgG, no specific predictions regarding seropositivity or exposure due to extensive cross-reactivity with dengue virus (DENV) serology could be made...

Immune responses are largely regulated by cytokines. Genetic polymorphisms of the regulatory coding regions are recognized to impact the expression of cytokines. The abnormal cytokine levels in hepatitis C virus (HCV) infection seems to be involved in disease progression, viral survival, and therapeutic response. The current study assesses the polymorphisms associated with IL-6, IL-10, IL28B, IFN-γ, TGF-β, and TNF-α on the genotypic susceptibility to HCV infection and Ribavirin response to Peg interferon...

The susceptibility levels of Malaysian Aedes albopictus larvae sampled from several agricultural, fogging-free residential and dengue prone residential areas against different larvicides were evaluated using revised diagnostic doses derived from the 2xLC99 values of the reference strain. Upon 24-hour recovery period of WHO larval bioassay, incipient resistance was observed among Ae. albopictus larvae from rubber estates against fenitrothion (96.67% mortality) and permethin (97.00% mortality) while Ae. albopictus larvae from rice cultivation areas were moderately resistant to fenthion (94...

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus with widespread distribution across the globe. Since 2016, CHIKV re-emerged in several countries including Indian subcontinent and Southeast Asia. A proper diagnostic tool for early diagnosis of CHIKV infection is crucial to facilitate patient management and control virus transmission at the earliest stage of outbreak. Therefore, a TaqMan minor groove binder (MGB) probe-based quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was developed to detect and quantify the CHIKV...

Trichomonas tenax, an oral flagellated protozoon found in humans, potentially associated with the inflammation of periodontal tissues and decreased immunity that causes the tissue damage and tooth loss from chronic infection. Currently, there is a lack of data regarding the prevalence of T. tenax infection in Thailand. Therefore, this study aimed to measure prevalence of T. tenax in periodontal disease patients by using polymerase chain reaction (PCR) to amplify the 18S ribosomal RNA (18S rRNA) gene and to determine the factors associated with the presence of this protozoan...

Porcine circovirus type 4 (PCV4) is the newest member in the porcine circovirus family, first reported in 2020. To date, the presence of PCV4 has only been reported in China, South Korea and most recently in Thailand. Detection of PCV4 have been reported in various production stages of pigs from piglets, finishers to sows; associated with a myriad of clinical manifestations including porcine dermatitis and nephropathy syndrome (PDNS), postweaning multisystemic wasting syndrome (PMWS), respiratory, enteric and neurological diseases...

In Malaysia presently, the main cause of human malaria is by the zoonotic monkey parasite Plasmodium knowlesi. A previous study has suggested that the P. knowlesi merozoite surface protein 1 (Pkmsp-1) block IV to be a suitable multiplicity of infection (MOI) genotyping marker for knowlesimalaria. This study therefore aimed to investigate the usefulness of Pkmsp-1 block IV in assessing the MOI of P. knowlesi in clinical isolates from Malaysia. Two allele-specific PCR primer pairs targeting the two allelic families of block IV (T1 and T2) were designed, and used to genotype P...

Melioidosis is endemic in Southeast Asia, including Malaysia. Liver abscess is not uncommon in melioidosis, but it is usually associated with bacteremia. We presented a case of a 55-year-old gentleman with underlying end-stage renal failure who presented with non-specific abdominal pain for three months. Initial blood investigations showed leukocytosis and increased C-reactive protein. Computed tomography (CT) of the abdomen revealed multiple hypodense lesions in the liver and spleen. The culture of the liver specimen obtained through the ultrasound-guided isolated Burkholderia pseudomallei...

The intake of food and water containing the Sarcocystis parasite has been linked to a number of outbreaks worldwide, including Malaysia. Nevertheless, the lack of surveys and epidemiological data on Sarcocystis infections in Malaysia makes it difficult to estimate its occurrence in humans and animals. A cross-sectional study was conducted to determine the prevalence of Sarcocystis and the risk factors associated with infection among village chickens and pigs reared under different farm managements in Peninsular Malaysia...

Most of the public health importance coronaviruses, such as Severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2 are likely originated from bats and spread to humans through intermediate hosts; civet cats, dromedary camel and Malayan pangolin, respectively. SARS-CoV-2-like coronaviruses were detected in Thailand, which is neighbouring with Kelantan in East Coast Malaysia. To date, there is no report on the presence of public health concerns (SARS-CoV, SARS-CoV-2 and MERS-CoV) coronaviruses in bats from Malaysia...

Simulium takahasii (Rubtsov), which was originally described from Japan, and recorded from Korea and China, is the first among the 19 species of the subgenus Wilhelmia Enderlein recorded from East Asia. It is striking in mating, blood-feeding and ovipositing in captivity and in experimentally transmitting Dirofilaria immitis (Leidy) and Brugia pahangi (Buckley & Edeson), and it is a severe biter of cattle and horses, rarely of humans. Nevertheless, updated information about its morphological characteristics was lacking, making comparisons with related species described from China difficult, since species of the subgenus Wilhelmia are almost indistinguishable from one another, in particular, in their female terminalia, male genitalia and most of larval features...

Leishmaniasis is an infectious disease with various clinical manifestations. We studied the therapeutic effects of Elettaria cardamomum essential oil (ECEO) against Leishmania major infection. In vitro effects of ECEO against L. major were examined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and macrophage assays. Nitric oxide (NO) production, infection inhibition in macrophages, and the apoptotic activity of ECEO in treated parasites were also measured. By calculating the 50% cytotoxic concentrations (CC50 ), we studied the cytotoxicity effects of ECEO on human macrophage cells (THP-1)...

Black soldier fly (Hermetia illucens (Linnaeus, 1758)) larvae inhibit oviposition of house fly (Musca domestica Linnaeus, 1758) by releasing a semiochemical, although in some situations, inhibition is only partial. We hypothesized that there is a certain period in the life cycle of black soldier fly when it can cause antibiosis of the house fly. Choice and non-choice tests were used to separately examine the effectiveness of each developmental stage of black soldier fly (egg, larval (phase I, II, and III), prepupal and pupal stages) and crude extract of larvae on house fly oviposition...

Leishmaniasis is a widely spread zoonotic disease caused by the bite of infected sandflies, particularly in developing countries. Cutaneous leishmaniasis can have a diverse range of presentations, ranging from minor skin nodules to significant mucosal damage. However, nose involvement is infrequent. Our report highlights a 15-year-old female patient with a persistent skin lesion on her nose for three months, which is a rare manifestation of cutaneous leishmaniasis. The lesion started as a raised spot with a brownish-red color and a crust but eventually developed into an ulcer that spread over the entire lobe of the nose and even moved toward the eye...

The development of new alternatives strategies to synthetic insecticides aimed at reducing pest populations by developing pesticides based on plant extracts without negative effects in non target organisms and environment. The present study was undertaken in order to assess the insecticidal activity of the crude methanolic extract of the Algerian Asteraceae Cotula cinerea, against the larval and the pupal stage of Culex pipiens (Diptera: Culicidae). It is also to determine the chemical composition of the used extract, and to understand the mechanism of toxic action of the tested extract...

Oriental theileriosis caused by Theileria orientalis is a growing health concern of lactating cows in its endemic areas. Rapid and sensitive diagnostic tests are demand areas for appropriate and effective prophylactic and therapeutic measures. Quantitative polymerase chain reaction (qPCR) is the answer for both detection and quantification of parasites. Present study deals with qPCR for detection of parasitemia level of T. orientalis in apparently healthy and clinically affected cows. Major piroplasm surface protein (MPSP) gene present in T...

Wild aquatic birds are natural reservoirs of influenza A viruses and H3 subtype is one of the most prevalent subtypes in waterfowl. Two H3N8 viruses of low pathogenic avian influenza (LPAI) were isolated via egg inoculation technique from the fecal swab specimens from imported barnacle goose and paradise shelduck in Veterinary Research Institute Ipoh, Malaysia. The full length of eight gene segments of the two viruses were amplified and sequenced with specific primers. The sequences were molecularly characterized, and the sequence identity were assessed with other published sequences...

Timely and rapid diagnosis is crucial for faster and proper malaria treatment planning. Microscopic examination is the gold standard for malaria diagnosis, where hundreds of millions of blood films are examined annually. However, this method's effectiveness depends on the trained microscopist's skills. With the increasing interest in applying deep learning in malaria diagnosis, this study aims to determine the most suitable deep-learning object detection architecture and their applicability to detect and distinguish red blood cells as either malaria-infected or non-infected cells...

Post-COVID-19 conditions encompass a wide range of health problems, including enteritis, but their association with parasitic infections has not yet been investigated. This study analyzed gastrointestinal symptoms, medical histories, fecal Cryptosporidium oocysts, and the history of COVID-19 infection in patients who attended the Faculty of Medicine, Cairo University, from January to July 2021. Fecal biomarkers, including H. pylori, occult blood, fecal calprotectin (FCAL), and TNF-a, were measured, and Cryptosporidium spp...

We have previously isolated a novel avian Orthobunyavirus, Kedah Fatal Kidney Syndrome (KFKS) virus from a broiler farm in Kedah, Malaysia in 2020 with a severe kidney lesion in chickens. The virus was designated as KFKS2_CS virus. Sequence analysis of partial nucleocapsid (N) and nonstructural (NSs) sequence of this virus showed the highest sequence identity with previous KFKS1 from Malaysia (100%) and 97% with a zoonotic Umbre (UMB) virus, which was reported to cause encephalitis in immunocompromised humans in India...