House dust mites and storage mites are well-known causes for allergenic diseases. The aim of this study was to investigate the immunogenic sites of Blomia tropicalis, Aleurogyphus ovatus and Glycycometus malaysiensis. The mites were maintained in a culture medium at 25ºC and 75% relative humidity. Mites were harvested either with heat escape or floatation method, purified, homogenized, quantified and used for the production of polyclonal antibody and immunostaining. For each species of mites, five male mice and five male rats were randomly selected and immunized intraperitoneally with respective crude mite extract at two-weekly intervals. Blomia tropicalis, A. ovatus or G. malaysiensis whole mites and paraffin-embedded mite sections were immunostained with the respective polyclonal antibody. The faecal pellets of mites were intensely stained for all the three species in the present study. The legs of sectioned A. ovatus were not immunogenic as compared with those of G. malaysiensis and B. tropicalis. The outer layer (cuticle) of whole mites and the eggs for these species were very immunogenic. Hence, the polyclonal antibodies obtained in this study may serve as potential tools in detecting the eggs and immature mites in environmental samples. Future studies should focus on the antigenic components of eggs since they were relatively abundant in dust and highly antigenic as seen in the present study.
Many finer taxonomic characters of Blomia tropicalis are not distinctly visible under conventional light microscopy. Scanning electron micrographs of this mite are therefore presented in this paper for better appreciation of the inconspicuous features of the morphology of the species. The differences in morphology of male and female B. tropicalis are also briefly discussed.
A comprehensive 8-yr survey of acarine ectoparasites (ticks and mites) of bats was carried out in 18 localities from 2002 to 2009. Most of the surveys were conducted during 14 national biodiversity scientific expeditions throughout Malaysia. The objective was to identify acarines of known public health importance from bats and thus determine whether there is any potential public health risk in Malaysia. Trapping of bats was conducted using Harp traps and Mist nets. In total, 1,579 individuals comprising of 6 families and 52 species of bats were examined alive. In general, 25.6% of the bats were infested with acarines. Infestation rates of ticks, mesostigmatid mites, and chiggers on bats examined were 0.4, 10.4, and 14.7%, respectively. Their prevalence and mean intensity were tabulated. Genera of ticks extracted were Amblyomma, Dermacentor, Ixodes, and Ornithodoros. Of these genera, only two species can be identified to species level and they are Amblyomma cordiferum and Ixodes simplex. In total, 8 genera and 15 species of mesostigmatid mites were found; the species were Ancystropus eonycteris, Ancystropus zeleborii, Echinonysus nasutus, Laelaps aingworthae, Laelaps nuttalli, Laelaps sanguisugus, Laelaps sculpturatus, Longolaelaps longulus, Longolaelaps whartonii, Meristaspis lateralis, Meristaspis macroglossi, Paraperiglischrus rhinolophinus, Spinturnix acuminatus, Spinturnix americanus, and Spinturnix bakeri. Chiggers on bats were represented by 12 genera and 6 species; the species identified were Gahrliepia fletcheri, Riedlinia lipoxena, Trombigastia cadei, Walchiella impar, Walchiella oudemansi, and Whartonia caobangensis. The study produced an up-to-date list of acarine ectoparasites of bats in Malaysia where a total of 38 genera and 47 species of acarines were listed. Findings of the study demonstrated that 5 genera and 1 species of acarines that may pose potential health risks, can be found on bats.
Orientia tsutsugamushi is the causative agent of scrub typhus vectored by larval stages of trombiculid mites (chiggers) that occur in most tropical regions of Southeast Asia. A total of 242 chiggers extracted from eight small mammals captured from a positive scrub typhus locality in Kelantan, Malaysia, were screened for the presence of O. tsutsugamushi. The chiggers were grouped in 16 pools for extraction of DNA prior to screening of O. tsutsugamushi based on the nucleotide sequence of 56-kDa type specific antigen (TSA) gene using nested polymerase chain reaction. Two species of on-host chiggers were identified, the one, Leptotrombidium deliense, much more dominant (94.8%) than the other, Ascoshoengastia sp. (5.2%). The pathogen was detected in two pools (12.5%) of L. deliense recovered from Rattus rattus and Tupaia sp. The 56-kDa TSA gene sequence analysis revealed the O. tsutsugamushi harboured in those chiggers were Karp prototype strain with high similarity (99.3%). Findings of this study strongly supported the existence of scrub typhus infections in certain parts of Malaysia which agrees with previous local reports. Moreover, this study highlighted the pressing need of a large-scale close observation of O. tsutsugamushi DNA sequences from chiggers that can probably be collected from other positive scrub typhus localities to precisely provide the distribution and prevalence of this zoonotic pathogen.
A species of house dust mite, Suidasia pontifica, was recently shown to produce allergens affecting man. The species may be as important as other allergen producing mite in sensitization and causing allergic symptoms in Malaysians. Surveys conducted demonstrated that 80% of the houses surveyed were positive for this mite with densities ranged from 2 to 50 mites per gram of dust. Colonies of the species has been successfully established and materials from those colonies have been used to produce extracts for studies on sensitization to the mites. A total of 85 suspected allergic rhinitis patients were tested and 74.1% demonstrated positive reactions. Extract of this mite should be considered for routine diagnostic testing and possible immunotherapy.
To identify the presence of acarine ectoparasites and determine whether there is any potential public health risk in Panti Forest Reserve, Johore, Malaysia.
The stages of decomposition and the faunal succession on rabbit carcasses in three different habitats, namely jungle, rural, and highland areas, were studied. Three New Zealand White rabbit (Oryctolagus cuniculus) carcasses weighing ∼2 kg were sampled daily until the decomposition process was completed. Representative specimens of adult flies, larvae, pupa, and mites were collected from the carcasses and processed in the laboratory. There were differences in decomposition rate and faunal succession between the carcasses. The fastest rate of decomposition was recorded in rural area, and the slowest rate of decomposition was recorded in highland area. The carcasses exhibited the same pattern of colonization by adult flies, but the dominant species of larvae and adult flies on each carcass in specific habitats were different. The primary species of flies recorded in jungle were Chrysomya megacephala F., Chrysomya rufifacies (Macquart), Chrysomya chani Kurahashi, Chrysomya villenuevi Patton, Chrysomya nigripes Aubertin, Chrysomya pinguis (Walker), Hemipyrellia ligurriens (Wiedemann), Hemipyrellia tagaliana (Bigot), Hypopyiopsis fumipennis (Walker), Hypopygiopsis violacea (Macquart), and Hydrotaea spinigera Stein represented by both adults and larvae. Musca domestica L., Atherigona sp., Lioproctia pattoni (Senior-White), Lioproctia saprianovae Pape & Bänziger, and Seniorwhitea princeps (Wiedemann) were represented by adults only. The biodiversity of flies in the rural area were C. megacephala, C. rufifacies, H. ligurriens, Fannia canicularis L., Hydrotaea chalcogaster (Wiedemann), and Hyd. spinigera represented by both adults and larvae, meanwhile M. domestica, Atherigona sp., Boettcherisca peregrina (Robineau-Desvoidy), Parasarcophaga taenionota Wiedemann, Parasarcophaga scopariiformis Senior-White, and S. princeps were represented by adults only. The species of flies collected in the highland area were Lucilia porphyrina (Walker), C. megacephala, C. rufifacies, C. villenuevi, C. pinguis, H. ligurriens, Hyd. spinigera, Hyd. chalcogaster, F. canicularis, and Boettcherisca highlandica Kurahashi & Tan represented by both adults and larvae, whereas C. nigripes, Chrysomya thanomthini Kurahashi & Tumrasvin, M. domestica, Atherigona sp., Parasarcophaga albiceps Meigen, P. taenionota, Sepsidae, Phoridae, and Millichidae were represented by adults only. Faunal succession followed the sequence of dominant flies, i.e., Calliphoridae, Sarcophagidae, Muscidae, Sepsidae, and lastly Stratiomyidae for jungle, or Sepsidae for rural and highland studies. Mites, from suborders Mesostigmata, Prostigmata, Astigmatina, and Oribatida, were also recovered throughout decomposition, which could be used for future implementation in forensic investigations. The data obtained from this study could provide more accurate indicators for local forensic scientists in solving criminal cases especially on the determination of time and primary location of death.
A considerable number of rat-borne ectoparasite studies have been conducted since the early 1930s in the Malayan Peninsula (now known as peninsular Malaysia). The majority of studies were field surveys and collections of specimens across the region, and were conducted primarily to catalogue the ectoparasite host distribution and discover novel species. This has generated a signification amount of information, particularly on the diversity and host distribution; other aspects such as morphology, host distribution and medical significance have also been investigated. Amongst the four main groups (mites, fleas, ticks, lice), rat-borne mites have received the most attention with a particular emphasis on chiggers, due to their medical importance. More recent studies have examined the distribution of ectoparasites in rats from different habitat type simplicating a high prevalence of zoonotic species infesting rat populations. Despite being capable of transmitting dangerous pathogens to human, the health risks of rat-borne ectoparasites appear to be small with no serious outbreaks of diseases recorded. Although an extensive number of works have been published, there remain gaps in knowledge that need to be addressed, such as, the distribution of under studied ectoparasite groups (listrophorids and myobiids), determining factors influencing infestation, and understanding changes to the population distribution over time.
Atopy is a syndrome characterized by immediate hypersensitivity reactions to common environmental antigens. The "hygiene hypothesis" stipulates that childhood infections are associated with a lower risk of allergies. Not much has been published about the effects that the treatment of pulmonary tuberculosis (TB) has on allergies, specifically allergic rhinitis. We conducted a study to investigate the prevalence of allergic rhinitis in patients with pulmonary TB before and after treatment of their TB. Our initial study group was made up of 121 patients with confirmed pulmonary TB who were followed up by questionnaire. In addition to demographic data, they provided information about their personal and family history of atopy and their current status with regard to allergic rhinitis. After providing informed consent, all patients underwent skin-prick testing with Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis allergens before and after TB treatment. Stool samples were obtained to identify patients with worm infestation, and they were excluded from the study. In all, 94 patients completed treatment and follow-up, and their data were included in the final analysis. Of this group, 31 patients (33.0%) exhibited symptoms of allergic rhinitis prior to TB treatment, and 26 (27.7%) had a positive skin-prick test. Following treatment, only 12 patients (12.8%) reported allergic rhinitis symptoms (p = 0.004), but there was no significant reduction in the number of patients with a positive skin-prick test (n = 20 [21.3%]; p = 0.555). We conclude that the treatment of pulmonary TB results in significant relief of atopy, particularly allergic rhinitis symptoms.