Displaying publications 61 - 80 of 98 in total

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  1. Fulltext Pathogenicity of Nosema sp. (Microsporidia) in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)
    Kermani N, Abu-Hassan ZA, Dieng H, Ismail NF, Attia M, Abd Ghani I
    PLoS One, 2013;8(5):e62884.
    PMID: 23675435 DOI: 10.1371/journal.pone.0062884
    Biological control using pathogenic microsporidia could be an alternative to chemical control of the diamondback moth (DBM) Plutella xylostella (Lepidoptera: Plutellidae). The microsporidium Nosema bombycis (NB) is one of the numerous pathogens that can be used in the Integrated Pest Management (IPM) of DBM. However, its pathogenicity or effectiveness can be influenced by various factors, particularly temperature. This study was therefore conducted to investigate the effect of temperature on NB infection of DBM larvae. Second-instar larvae at different doses (spore concentration: 0, 1×10²,1×10³,1×10⁴, and 1×10⁵) at 15°, 20°, 25°, 30° and 35°C and a relative humidity(RH) of 65% and light dark cycle (L:D) of 12∶12. Larval mortality was recorded at 24 h intervals until the larvae had either died or pupated. The results showed that the spore concentration had a significant negative effect on larval survival at all temperatures, although this effect was more pronounced (92%) at 35°C compared with that at 20 and 30°C (≃50%) and 25°C (26%). Histological observations showed that Nosema preferentially infected the adipose tissue and epithelial cells of the midgut, resulting in marked vacuolization of the cytoplasm. These findings suggest that Nosema damaged the midgut epithelial cells. Our results suggest that Nosema had a direct adverse effect on DBM, and could be utilized as an important biopesticide alternative to chemical insecticides in IPM.
    Matched MeSH terms: Larva/growth & development
  2. Fulltext Changing domesticity of Aedes aegypti in northern peninsular Malaysia: reproductive consequences and potential epidemiological implications
    Saifur RG, Dieng H, Hassan AA, Salmah MR, Satho T, Miake F, et al.
    PLoS One, 2012;7(2):e30919.
    PMID: 22363516 DOI: 10.1371/journal.pone.0030919
    BACKGROUND: The domestic dengue vector Aedes aegypti mosquitoes breed in indoor containers. However, in northern peninsular Malaysia, they show equal preference for breeding in both indoor and outdoor habitats. To evaluate the epidemiological implications of this peridomestic adaptation, we examined whether Ae. aegypti exhibits decreased survival, gonotrophic activity, and fecundity due to lack of host availability and the changing breeding behavior.

    METHODOLOGY/PRINCIPAL FINDINGS: This yearlong field surveillance identified Ae. aegypti breeding in outdoor containers on an enormous scale. Through a sequence of experiments incorporating outdoors and indoors adapting as well as adapted populations, we observed that indoors provided better environment for the survival of Ae. aegypti and the observed death patterns could be explained on the basis of a difference in body size. The duration of gonotrophic period was much shorter in large-bodied females. Fecundity tended to be greater in indoor acclimated females. We also found increased tendency to multiple feeding in outdoors adapted females, which were smaller in size compared to their outdoors breeding counterparts.

    CONCLUSION/SIGNIFICANCE: The data presented here suggest that acclimatization of Ae. aegypti to the outdoor environment may not decrease its lifespan or gonotrophic activity but rather increase breeding opportunities (increased number of discarded containers outdoors), the rate of larval development, but small body sizes at emergence. Size is likely to be correlated with disease transmission. In general, small size in Aedes females will favor increased blood-feeding frequency resulting in higher population sizes and disease occurrence.

    Matched MeSH terms: Larva/growth & development
  3. Fulltext Molecular identification of Trichinella papuae from a Thai patient with imported trichinellosis
    Intapan PM, Chotmongkol V, Tantrawatpan C, Sanpool O, Morakote N, Maleewong W
    Am J Trop Med Hyg, 2011 Jun;84(6):994-7.
    PMID: 21633039 DOI: 10.4269/ajtmh.2011.10-0675
    Previously, we reported the presence of imported trichinellosis in a Thai worker returning from Malaysia, who presented with progressive generalized muscle hypertrophy and weakness after eating wild boar meat. This work analyzed a partial small subunit of a mitochondrial ribosomal RNA gene of Trichinella larvae isolated from the patient. The results showed complete identity with a mitochondrial RNA gene of Trichinella papuae (GenBank accession no. EF517130). This is the first report of imported trichinellosis in Thailand caused by T. papuae. It is possible that T. papuae is widely distributed in the wildlife of Southeast Asia.
    Matched MeSH terms: Larva/growth & development
  4. Recovery of forensically important insect larvae from human cadavers in Malaysia (1993-1996)
    Lee HL
    Malays J Pathol, 1996 Dec;18(2):125-7.
    PMID: 10879234
    Forensically important entomological specimens recovered from 95 forensic cases of human cadavers from April 1993 to May 1996 in Malaysia were identified and analysed. The results indicated that 73.7% of these specimens were Chrysomya species, occurring either as single or mixed infestations. Of these, the most prominent species were Ch megacephala (F.) and Ch rufifacies (Macquart). Other fly maggots recovered included Sarcophaga spp., Lucilia spp. and Hermetia spp., mostly occurring together with other calliphorine flies. A member of Muscidae fly, Ophyra spp. was also recovered for the first time.
    Matched MeSH terms: Larva/growth & development
  5. Larval growth of Liosarcophaga dux Thompson (Diptera: Sarcophagidae) under uncontrolled indoor temperatures in Malaysia
    Kumara TK, Hassan AA, Salmah MR, Bhupinder S
    Southeast Asian J. Trop. Med. Public Health, 2013 Mar;44(2):182-7.
    PMID: 23691627
    The larval growth of Liosarcophaga dux Thompson (Diptera: Sarcophagidae) was studied under varying indoor room temperatures in Malaysia. Five replicates were established. The immature growth of this species from first instar until adult emergence was 307.0+/-3.0 hours. The mean larval length measured for second instar, third instar, post-feeding stage and puparia were 6.5+/-0.5 mm (n=10), 11.8+/-3.7 mm (n=31), 12.7+/-0.8 mm (n=16), and 9.5+/-0.5 mm (n=15), respectively.
    Matched MeSH terms: Larva/growth & development
  6. Relationship between rainfall and Aedes larval population at two insular sites in Pulau Ketam, Selangor, Malaysia
    Wee LK, Weng SN, Raduan N, Wah SK, Ming WH, Shi CH, et al.
    Southeast Asian J. Trop. Med. Public Health, 2013 Mar;44(2):157-66.
    PMID: 23691624
    Two insular settlements (Kampung Pulau Ketam and Kampung Sungai Lima) were selected to study the population dynamics of Aedes aegypti and Aedes albopictus mosquitoes, vectors of dengue and chikungunya infections. Ovitrap surveillance was conducted between October 2007 and October 2008. There was an inverse negative association between ovitrap index and rainfall at the time of collection, probably because rainfall increased the number of available oviposition sites. Rainfall and ovitrap index were positively associates the 25th day after rainfall occurred. A minor, second peak was observed from the 38th to the 42nd day. The first peak was consistent with the minimum 18-day period between the hatching of eggs to the first oviposition. The second minor peak could be due to the second gonotrophic cycle of the female mosquitoes. Rainfall is an important environmental factor associated with Aedes breeding at the study sites.
    Matched MeSH terms: Larva/growth & development
  7. Life tables study of immature Aedes albopictus (Skuse) (Diptera : Culicidae) during the wet and dry seasons in Penang, Malaysia
    Hashim NA, Ahmad AH, Rawi CS, Tahir NA, Basari N
    Southeast Asian J. Trop. Med. Public Health, 2008 Jan;39(1):39-47.
    PMID: 18567442
    Life tables were constructed for twelve cohorts of immature stages of the dengue vector Ae. albopictus in a wooded area of Penang, Malaysia. The development time of Ae. albopictus ranged from 6 to 10 days depending on the mean environmental temperature (r = - 0.639, p < 0.05). Total cohort mortality was correlated with total development time (r = 0.713, p < 0.05) but not temperature (r = -0.477, p > 0.05). Rainfall was correlated with neither development time (r = 0.554, p > 0.05) nor mortality (r = 0.322, p > 0.05). There was a significant difference among the total mortality that occurred in the twelve cohorts (H = 119.783, df = 11, p < 0.05). There was also a significant difference in mortality among the different stages (H = 274.00, df = 4, p < 0.05).
    Matched MeSH terms: Larva/growth & development
  8. ABSENCE OF AEDES AEGYPTI (L.) ON AN ECOLOGICAL ISLAND: COMPETITIVE EXCLUSION?
    Afizah AN, Mahirah MN, Azahari AH, Asuad MK, Nazni WA, Lee HL
    Southeast Asian J. Trop. Med. Public Health, 2015 Sep;46(5):850-6.
    PMID: 26863856
    Ovitrap surveillance was conducted in 2012 and 2006 in Malay and Aboriginal Villages on Carey Island. In each village, standard ovitraps were placed indoors and outdoors at randomly selected houses/locations. All L3 larvae recovered were identified up to species level. Results demonstrated that only larvae of Aedes albopictus were found in all the positive ovitraps placed indoors and outdoors. In 2012, a high ovitrap index (OI) of 66.7% indoor and 84.0% outdoor in the Malay Village; and 62.5% indoor and 88.0% outdoor in Aboriginal Village with an apparent absence of Aedes aegypti. In 2006, a 100% OI was recorded in all ovitraps set indoors and outdoors in both villages.
    Matched MeSH terms: Larva/growth & development
  9. Fulltext Life-cycle, longevity and fecundity of Blomia tropicalis (Acari: Glycyphagidae) in a tropical laboratory
    Mariana A, Ho TM, Heah SK
    Southeast Asian J. Trop. Med. Public Health, 1996 Jun;27(2):392-5.
    PMID: 9280009
    In the present study on the life-cycle of Blomia tropicalis, freshly laid eggs were observed until they developed into adults; the development periods between stages were recorded. The eggs took an average of 22.9 +/- 6.4 days to develop to adults. For longevity experiments, newly emerged adults were kept at 25 degrees C and observed until they died. There was no significant difference in longevities of the different sexes (p = 0.053). Production of eggs by mated females were monitored until egg production stopped and the female died. Mated females and males survived an average of 32.2 +/- 15.4 and 30.9 +/- 17.7 days respectively. The difference in longevity of the mated females, and males was not significant (p = 0.747). Longevity of the mated females was found to be significantly (p < 0.05) shorter than unmated females.
    Matched MeSH terms: Larva/growth & development
  10. Update on the bionomics of Mansonia vectors of brugian filariasis
    Chiang GL
    Southeast Asian J. Trop. Med. Public Health, 1993;24 Suppl 2:69-75.
    PMID: 7973951
    The genus Mansonia is divided into two subgenera, Mansonia and Mansonioides. The subgenus Mansonioides includes the important vectors of lymphatic filariasis caused by Brugia malayi in South and Southeast Asia. Six species of this subgenus are vectors of two types of brugian filariasis, periodic and subperiodic. All six species, viz Mansonia bonneae, Ma. dives, Ma. uniformis, Ma. annulifera, Ma. annulata and Ma. indiana are present in this country. The ecological factors governing the larval and adult biology and their control measures are discussed.
    Matched MeSH terms: Larva/growth & development
  11. Fulltext The ecology of anopheline mosquitos in northwest coastal Malaysia: larval habitats and adult seasonal abundance
    Jaal Z, Macdonald WW
    Southeast Asian J. Trop. Med. Public Health, 1993 Sep;24(3):522-9.
    PMID: 8160063
    Collections of anopheline mosquitos were made twice monthly for 13 months from a cow-baited trap in two villages, Kampung Permatang Rawa and Sungai Udang Kecil, on mainland coastal Penang, Malaysia. Each collection period was six hours from sunset. Unquantified larval collections were made regularly in each area. Although the villages were only about 50km apart, and each had extensive, irrigated rice-fields in its vicinity, the species abundance and the seasonal fluctuations differed significantly. In Kampung Permatang Rawa Anopheles sinensis and An. peditaeniatus were dominant in prevalence, whereas in Sungai Udang Kecil An. indefinitus and An. lesteri paraliae were most common and An. peditaeniatus was relatively rare. The rice growing schedules in the two areas differed, but there was a moderate correlation between the abundance of several species and the rice-growing pattern. There was no correlation at either site with rainfall.
    Matched MeSH terms: Larva/growth & development
  12. The life history of a colony of Leptotrombidium (Leptotrombidium) fletcheri (Womersley & Heaslip) infected with Rickettsia tsutsugamushi
    Dohany AL, Upham RW, Manikumaran C, Rapmund G, Saunders JP
    Southeast Asian J. Trop. Med. Public Health, 1977 Jun;8(2):221-6.
    PMID: 411178
    The life cycle of 5 generations of Leptotrombidium (L.) fletcheri infected with Rickettsia tsutsugamushi and reared under ambient temperatures in Malaysia was presented and compared with a colony reared at a constant 27 degrees C (Neal and Barnett, 1961). In general our colony had a longer generation time (average of 54 days from engorged larvae to adult compared with 37 days) and produced fewer eggs (average of 127.9 compared with 900.0) than the comparison colony. Possible factors causing these differences are discussed.
    Matched MeSH terms: Larva/growth & development
  13. The inheritance of autogeny in Aedes (Finlaya) togoi (Theobald) from Malaysia and some aspects of its biology
    Thomas V, Leng YP
    Southeast Asian J. Trop. Med. Public Health, 1972 Jun;3(2):163-74.
    PMID: 5082846
    Matched MeSH terms: Larva/growth & development
  14. Fulltext Effects of delayed metamorphosis on larval survival, metamorphosis, and juvenile performance of four closely related species of tropical sea urchins (genus Echinometra)
    Rahman MA, Yusoff FM, Arshad A, Uehara T
    ScientificWorldJournal, 2014;2014:918028.
    PMID: 24624048 DOI: 10.1155/2014/918028
    We report here, the effects of extended competency on larval survival, metamorphosis, and postlarval juvenile growth of four closely related species of tropical sea urchins, Echinometra sp. A (Ea), E. mathaei (Em), Echinometra sp. C (Ec), and E. oblonga (Eo). Planktotrophic larvae of all four species fed on cultured phytoplankton (Chaetoceros gracilis) attained metamorphic competence within 22-24 days after fertilization. Competent larvae were forced to delay metamorphosis for up to 5 months by preventing them from settling in culture bottles with continuous stirring on a set of 10 rpm rotating rollers and larval survival per monthly intervals was recorded. Larval survival was highest at 24 days, when competence was attained (0 delayed period), and there were no significant differences among the four species. Larvae that had experienced a prolonged delay had reduced survival rate, metamorphosis success, and juvenile survival, but among older larvae, Em had the highest success followed by Ea, Eo, and Ec. Juveniles from larvae of all four species that metamorphosed soon after becoming competent tended to have higher growth rates (test diameter and length of spines) than juveniles from larvae that metamorphosed after a prolonged period of competence with progressively slower growth the longer the prolonged period. Despite the adverse effects of delaying metamorphosis on growth parameters, competent larvae of all four species were able to survive up to 5 months and after metamorphosis grew into 1-month-old juveniles in lab condition. Overall, delayed larvae of Em showed significantly higher larval survival, metamorphosis, and juvenile survival than Ea and Eo, while Ec showed the lowest values in these performances. Em has the most widespread distribution of these species ranging from Africa to Hawaii, while Ec probably has the most restricted distribution. Consequently, differences in distribution may be related to differences in the ability to delay metamorphosis.
    Matched MeSH terms: Larva/growth & development
  15. Fulltext Embryonic, larval, and early juvenile development of the tropical sea urchin, Salmacis sphaeroides (Echinodermata: Echinoidea)
    Rahman MA, Yusoff FM, Arshad A, Shamsudin MN, Amin SM
    ScientificWorldJournal, 2012;2012:938482.
    PMID: 23055824 DOI: 10.1100/2012/938482
    Salmacis sphaeroides (Linnaeus, 1758) is one of the regular echinoids, occuring in the warm Indo-West Pacific, including Johor Straits, between Malaysia and Singapore. In order to investigate the developmental basis of morphological changes in embryos and larvae, we documented the ontogeny of S. sphaeroides in laboratory condition. Gametes were obtained from adult individuals by 0.5 M KCl injection into the coelomic cavity. Fertilization rate at limited sperm concentration (10(-5) dilution) was 96.6 ± 1.4% and the resulting embryos were reared at 24°C. First cleavage (2-cell), 4-cell, 8-cell, 16-cell, 32-cell, and multicell (Morulla) stages were achieved 01.12, 02.03, 02.28, 02.51, 03.12, and 03.32 h postfertilization. Ciliated blastulae with a mean length of 174.72 ± 4.43 μm hatched 08.45 h after sperm entry. The gastrulae formed 16.15 h postfertilization and the archenteron elongated constantly while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larva started to feed unicellular algae in 2 d, grew continuously, and finally attained metamorphic competence in 35 d after fertilization. Metamorphosis took approximately 1 h 30 min from attachment to the complete resorption of larval tissues and the development of complete juvenile structure with adult spines, extended tubefeet and well-developed pedicellaria, the whole event of which usually took place within 1 d postsettlement. This study represents the first successful investigation on embryonic, larval, and early juvenile development of S. sphaeroides. The findings would greatly be helpful towards the understanding of ontogeny and life-history strategies, which will facilitate us to develop the breeding, seed production, and culture techniques of sea urchins in captive condition.
    Matched MeSH terms: Larva/growth & development*
  16. The molecular prevalence, distribution and risk factors associated with Babesia bigemina infection in Peninsular Malaysia
    Ola-Fadunsin SD, Sharma RSK, Abdullah DA, Gimba FI, Abdullah FFJ, Sani RA
    Ticks Tick Borne Dis, 2021 05;12(3):101653.
    PMID: 33465661 DOI: 10.1016/j.ttbdis.2021.101653
    Babesia bigemina is a tick-borne protozoan that affects cattle in almost all regions of the world. Despite its importance, there is no report of its prevalence in cattle using molecular detection methods in Peninsular Malaysia. This study describes the prevalence, distribution, and risk factors associated with B. bigemina infection using molecular diagnostic methods. Also, the species of ticks infesting cattle and the attitude of cattle farmers towards tick control in Peninsular Malaysia were studied. Blood samples were collected from 1045 cattle from 43 herds throughout the country, and were subjected to molecular studies to detect B. bigemina. Tick samples for entomological studies were also collected and identified. Epidemiological information of each cattle and farm were obtained using a well-structured questionnaire containing open-ended and closed-ended questions. Data were statistically analyzed using Univariate and Multivariate models. The 211-base pair of AMA-1 gene of B. bigemina was amplified and confirmed in 30.5 % (319/1045; 95 % CI = 27.8-33.4) of the sampled population, with the haemoprotozoan detected in all the sampled herds. Breed, age, physiological status, management type, rate of de-ticking, and closeness to human settlement were the risk factors significantly (p < 0.05) associated with the prevalence of B. bigemina in cattle. Rhipicephalus (Boophilus) microplus and Haemaphysalis bispinosa were the species of ticks collected from cattle, with the former been more prevalent. A large number of cattle farmers (12/43; 28 %) do not control ticks in their herds. The findings of this study will create baseline data on the epidemiology of the haemoprotozoan and control patterns of its tick vectors that will guide the government in enacting policies that will improve food security and the economy of the nation.
    Matched MeSH terms: Larva/growth & development
  17. Fulltext Distribution of mosquito larvae in various breeding sites in National Zoo Malaysia
    Muhammad-Aidil R, Imelda A, Jeffery J, Ngui R, Wan Yusoff WS, Aziz S, et al.
    Trop Biomed, 2015 Mar;32(1):183-6.
    PMID: 25801269 MyJurnal
    Mosquitoes are principal vectors of major vector-borne diseases. They are widely found throughout urban and rural areas in Malaysia. They are responsible for various vector-borne diseases such as dengue, malaria, filariasis and encephalitis. A total of 158 mosquito larvae specimens were collected from the National Zoo, Malaysia, from 11 types of breeding habitats during the study period from end of May 2007 to July 2007. Aedes albopictus was the predominant species (35.4%), followed by Tripteroides aranoides (26.6%), Lutzia halifaxii (11.4%), Aedes alboscutellatus (10.1%), Aedes caecus (8.9%), Armigeres spp. (4.4%), Malaya genurostris (2.5%) and Culex vishnui (0.6%). It is important to have a mosquito free environment in a public place like the zoo. Routine larval surveillance should be implemented for an effective mosquito control program in order to reduce mosquito population.
    Matched MeSH terms: Larva/growth & development
  18. Fulltext Larval aggregation on a burned human remain
    Kumara TK, Abu Hassan A, Che Salmah MR, Bhupinder S
    Trop Biomed, 2012 Mar;29(1):197-9.
    PMID: 22543622 MyJurnal
    A burned human remain was found outdoor (5º 27' N, 100º 16' E) in Penang Island. The deceased was last seen alive on 23 April 2010 at 2230 h and was found burned on 24 April 2010 at 1920 h. Larval aggregation of second instar Chrysomya megacephala was observed on the chest of the deceased.
    Matched MeSH terms: Larva/growth & development
  19. Fulltext Malathion extraction from larvae of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) for determining death due to malathion
    Mahat NA, Jayaprakash PT, Zafarina Z
    Trop Biomed, 2012 Mar;29(1):9-17.
    PMID: 22543598 MyJurnal
    The use of Chrysomya megacephala larvae for detecting malathion for diagnosing the cause of death was investigated. This could prove useful when the visceral organs have become liquefied during decomposition and therefore cannot be sampled. A field experiment was conducted in which C. megacephala were allowed to colonise naturally the corpses of rabbits that had died of malathion poisoning. The concentration of malathion increased gradually during the larval stages of C. megacephala reaching the maximum concentration in the third instar larvae. The concentration of malathion declined during prepupal stage and reached its lowest level among tenerals. The average malathion concentrations in C. megacephala growing in poisoned rabbit corpses left in a sunlit habitat were significantly higher (p<0.05) than those growing on poisoned rabbits left in a shaded habitat. The concentrations of malathion in the different stages of development of C. megacephala were moderately correlated (r = 0.51-0.69) with the administered doses as well as with those estimated in visceral organs. Thus, it would not be reliable to suggest the formulation of mathematical algorithms for relating the concentration of malathion found in the different stages of development of C. megacephala with those found in the visceral organs. However, in the context of forensic investigation, the qualitative detection of malathion in C. megacephala may prove useful in diagnosing the cause of death, since malathion is a common cause of accidental and suicidal deaths.
    Matched MeSH terms: Larva/growth & development
  20. Fulltext Field observation on the efficacy of Toxorhynchites splendens (Wiedemann) as a biocontrol agent against Aedes albopictus (Skuse) larvae in a cemetery
    Nyamah MA, Sulaiman S, Omar B
    Trop Biomed, 2011 Aug;28(2):312-9.
    PMID: 22041750
    This study explored the efficacy of Toxorhynchites splendens, predator of Aedes albopictus as a biocontrol agent. There was a negative correlation between Ae. albopictus larval population and Tx. splendens larval population in ovitraps (r=-0.287, R²=0.0821). The correlation is higher between the mean number of Ae. albopictus larvae per ovitrap and the number of Tx. splendens larvae in an ovitrap (r=-0.987, R²=0.9737). Larvae of Tx. splendens were observed to co-exist with larvae of Ae. albopictus and Culex fuscocephala in the ovitraps placed in the study area. The existence of Tx. splendens larvae in the study area coincides with their habit, preferring to breed in bamboo stumps. A total of 480 ovitraps were inspected for 30-week study period and 281 ovitraps were positive with Ae. albopictus larvae respectively. There was a significant difference between numbers of ovitrap positive for Ae. albopictus larvae with number of Tx. splendens larvae in the ovitraps (ANOVA, F((4,475)) 2.655, p<0.05). Of 281 ovitraps positive with Ae. albopictus larvae, 255 ovitraps contained only one Tx. splendens larva each. Only one ovitrap contained four, the most number of Tx. splendens larvae (p< 0.05). Thus, Tx. splendens could be utilised as an alternative for dengue vector control programme.
    Matched MeSH terms: Larva/growth & development
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