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Fulltext Quantitative real-time PCR analysis of Anopheles dirus TEP1 and NOS during Plasmodium berghei infection, using three reference genes

Liew JWK, Fong MY, Lau YL

PeerJ, 2017;5:e3577.
PMID: 28761783 DOI: 10.7717/peerj.3577

Quantitative reverse transcription PCR (qRT-PCR) has been an integral part of characterizing the immunity of Anopheles mosquitoes towards Plasmodium invasion. Two anti-Plasmodium factors of Anopheles, thioester-containing protein 1 (TEP1) and nitric oxide synthase (NOS), play a role in the refractoriness of Anopheles towards Plasmodium infection and are generally expressed during infection. However, these are less studied in Anopheles dirus, a dominant malaria vector in Southeast Asia. Furthermore, most studies used a single reference gene for normalization during gene expression analysis without proper validation. This may lead to erroneous quantification of expression levels. Therefore, the present study characterized and investigated the expression profiles of TEP1 and NOS of Anopheles dirus during P. berghei infection. Prior to that, the elongation factor 1-alpha (EF1), actin 1 (Act) and ribosomal protein S7 (S7) genes were validated for their suitability as a set of reference genes. TEP1 and NOS expressions in An. dirus were found to be significantly induced after P. berghei infection.

Matched MeSH terms: Disease Vectors
Over two decades of Plasmodium knowlesi infections in Sarawak: Trend and forecast

Ooi CH, Bujang MA, Tg Abu Bakar Sidik TMI, Ngui R, Lim YA

Acta Trop, 2017 Dec;176:83-90.
PMID: 28768148 DOI: 10.1016/j.actatropica.2017.07.027

Malaria is still of great public health concern, especially in Malaysian Borneo. The aim of this study was to determine the trends of P. knowlesi infection in Sarawak, Malaysia and to forecast the incidence of P. knowlesi until the year 2040. Data on P. knowlesi malaria cases from 1992 to the year 2014 were obtained from the Sarawak Health Department, Malaysia. ARIMA model was applied to forecast the future incidence of P. knowlesi infection. The data for the whole of Sarawak and subsequently the selected six districts which have high incidence rates of P. knowlesi infection were analyzed. Results of the analysis showed that there was an increasing trend of P. knowlesi cases from the year 1992-2014 (p<0.001). The trend in the incidence started to increase in the year 2008 (p=0.029). The incidence rate per 100,000 populations was between 4.15 in the year 1992 and 42.03 in the year 2014. High incidence of P. knowlesi infections has been detected in the districts adjacent to each other within the interior region of Sarawak. The forecasted incidence and incidence rate per 100,000 populations in the year 2020 were 1229 and 44.04, respectively, while those in the year 2040 were 2056 and 62.91, respectively. The forecasted incidence showed an upward trend highlighting an urgent need to draw up strategic and holistic prevention plans to limit further the increase in P. knowlesi morbidity and mortality in Sarawak. It is imperative that these measures are customized taking into consideration the challenges faced in the interior areas of Sarawak and the behavior of the main vector of P. knowlesi (i.e., An. latens) in Sarawak.

Matched MeSH terms: Disease Vectors
Fulltext Screening of five plant extracts for larvicidal efficacy against larvae of Aedes aegypti (L.) and Aedes albopictus (Skuse)

Azlinda Abu Bakar, Sallehudin Sulaiman, Baharudin Omar, Rasadah Mat Ali

ASM Science Journal, 2018;11(2):103-116.
MyJurnal

The adverse effects of prolonged and rampant usage of chemical insecticides in controlling the population of vector arthropod have caused the development of resistance among vector populations as well as non-target organism. Application of plant extracts could be alternative sources for mosquito control. The present study assessed larvicidal activities of methanol extracts of leaf and stem of Jacaranda mimosifolia Don (Family: Bignoniaceae), Melaleuca cajuputi Powell (Family: Myrtaceae), Tabebuia chrysantha (Jacq.) Nicholson (Family: Bignoniaceae), Tabebuia pallida (Lindl.) Miers (Family: Bignoniaceae) and Tabebuia rosea Toll (Family: Bignoniaceae) against dengue vectors, Aedes (Diptera: Culicidae) sp. Among plants tested, M. cajuputi exhibited the most effective with the highest mortality against Ae. aegypti and Ae. albopictus. Leaf extracts showed significantly higher larvicidal effects in relative to stem extracts. The findings also revealed that Ae. aegypti is the most susceptible compared to Ae. albopictus. LC50 values of M. cajuputi leaf extracts were 183.35mg/L and 191.82mg/L against Ae. aegypti and Ae. albopictus respectively. These studies suggest leaf extracts of M. cajuputi have moderate potential as larvicidal against vector larvae of Aedes mosquitoes.

Matched MeSH terms: Disease Vectors
An overview of rickettsiae in Southeast Asia: Vector-animal-human interface

Low VL, Tan TK, Khoo JJ, Lim FS, AbuBakar S

Acta Trop, 2020 Feb;202:105282.
PMID: 31778642 DOI: 10.1016/j.actatropica.2019.105282

Rickettsioses are emerging, and re-emerging diseases caused by obligate intracellular arthropod-borne bacteria that infect humans and animals worldwide. Various rickettsiae such as Orientia, Rickettsia, Anaplasma and Ehrlichia have been circulated in companion, domesticated and wild animals through bites of infected ticks, fleas, lice or mites. This review summarizes the infections of rickettsiae, including the newly discovered regional species Rickettsia thailandii, Candidatus Rickettsia sepangensis, Candidatus Rickettsia johorensis, Candidatus Rickettsia laoensis, Candidatus Rickettsia mahosotii, Candidatus Rickettsia khammouanensis, Candidatus Anaplasma pangolinii, and other novel genotypes in vectors, humans and animals in Southeast Asia. Issues on some unidentified rickettsiae that elicit immune responses and production of antibodies that are cross-reactive with the antigens used are discussed. Knowledge gaps which required attention are also identified in this review.

Matched MeSH terms: Disease Vectors
Fulltext Recent advances on the use of biochemical extracts as filaricidal agents

Al-Abd NM, Nor ZM, Al-Adhroey AH, Suhaimi A, Sivanandam S

Evid Based Complement Alternat Med, 2013;2013:986573.
PMID: 24298292 DOI: 10.1155/2013/986573

Lymphatic filariasis is a parasitic infection that causes a devastating public health and socioeconomic burden with an estimated infection of over 120 million individuals worldwide. The infection is caused by three closely related nematode parasites, namely, Wuchereria bancrofti, Brugia malayi, and B. timori, which are transmitted to human through mosquitoes of Anopheles, Culex, and Aedes genera. The species have many ecological variants and are diversified in terms of their genetic fingerprint. The rapid spread of the disease and the genetic diversification cause the lymphatic filarial parasites to respond differently to diagnostic and therapeutic interventions. This in turn prompts the current challenge encountered in its management. Furthermore, most of the chemical medications used are characterized by adverse side effects. These complications urgently warrant intense prospecting on bio-chemicals that have potent efficacy against either the filarial worms or thier vector. In lieu of this, we presented a review on recent literature that reported the efficacy of filaricidal biochemicals and those employed as vector control agents. In addition, methods used for biochemical extraction, screening procedures, and structure of the bioactive compounds were also presented.

Matched MeSH terms: Disease Vectors
Studies on the life cycle and developmental morphology of Cyclodontostomum purvisi (Adams, 1933) a hookworm parasite of Malayan giant rats

Varughese G

Southeast Asian J Trop Med Public Health, 1973 Mar;4(1):78-95.
PMID: 4718132
Matched MeSH terms: Disease Vectors
A preliminary report on the life cycle of Stephanofilaria kaeli

Mullin SW

Southeast Asian J Trop Med Public Health, 1971 Mar;2(1):84.
PMID: 5165245
Matched MeSH terms: Disease Vectors
Operational issues in the control of the vectors of Brugia

Chang MS

Ann Trop Med Parasitol, 2002 Dec;96 Suppl 2:S71-6.
PMID: 12625920

An estimated 13 million people in the Oriental Region have brugian filariasis. The filarial parasites that cause this disease exist in periodic and sub-periodic forms and are transmitted by four genera of mosquito: Anopheles, Mansonia and, less frequently, Coquillettidia and Ochlerotatus. In most endemic countries, control of the disease has been entirely based on chemotherapy, although house-spraying and use of insecticide-treated bednets can be quite effective against the vectors of nocturnally periodic Brugia malayi and B. timori. The vector-control methods that may be applied against the Mansonia mosquitoes that transmit the parasites causing sub-periodic brugian filariasis are reviewed here. Most of the conventional methods for controlling the immature, aquatic stages of mosquitoes have proved unsatisfactory against Mansonia. The reason is that, unlike the those of other genera, the larvae and pupae of Mansonia spp. are relatively immobile and obtain air not at the water surface but from the underwater roots, stems and leaves of floating plants to which the larvae and pupae attach. Removal of host plants can be very effective in reducing Mansonia productivity, whereas large-scale use of herbicides is restricted by the potential adverse effects on the ecosystem. Environmental management in water-development projects remains the best option.

Matched MeSH terms: Disease Vectors*
Involvement of small mammals in the transmission of scrub typhus in Malaysia: isolation and serological evidence

Walker JS, Gan E, Chan Teik Chye, Muul I

Trans R Soc Trop Med Hyg, 1973;67(6):838-45.
PMID: 4207572
Matched MeSH terms: Disease Vectors*
Isolation by culture and PCR identification of LipL32 gene of pathogenic Leptospira spp. in wild rats of Kuala Lumpur

Latifah I, Abdul Halim A, Rahmat MS, Nadia MF, Ubil ZE, Asmah H, et al.

Malays J Pathol, 2017 08;39(2):161-166.
PMID: 28866698 MyJurnal

BACKGROUND: A study was conducted to confirm the status of rats as the carrier of pathogenic leptospira in Kuala Lumpur, Malaysia.
METHOD: A total of 140 urine samples were collected from trapped rats. These samples were cultured in EMJH enriched media and 18 of these samples (12.9%) were found to be positive when observed under x40 by dark field microscope. Genomic DNA was extracted from all the 18 native isolates for PCR.
RESULT: All the 18 isolates generated the expected 786 base pair band when the set of primers known to amplify LipL32 gene were utilized. These results showed that the primers were suitable to be used for the identification of pathogenic leptospira from the 18 rat samples.
CONCLUSION: The sequencing of the PCR products and BLAST analysis performed on each representative isolates confirmed the pathogenic status of all these native isolates as the LipL32 gene was detected in all the Leptospira isolates. This indicates that the rats are carriers of the pathogenic leptospira in the study area, and therefore are of public health importance.

Matched MeSH terms: Disease Vectors*
Schistosomiasis transmission dynamics and control in Southeast Asia

Upatham ES

Southeast Asian J Trop Med Public Health, 1984 Dec;15(4):452-61.
PMID: 6535258
Matched MeSH terms: Disease Vectors*
Paragonimus and paragonimiasis

Yokogawa M

Adv Parasitol, 1969;7:375-87.
PMID: 4935271
Matched MeSH terms: Disease Vectors*
Fulltext Investigation of a suspected outbreak of Japanese encephalitis in Pulau Langkawi

Fang R, Hsu DR, Lim TW

Malays J Pathol, 1980 Aug;3:23-30.
PMID: 6312203
Matched MeSH terms: Disease Vectors
Clonorchis sinensis in West Malaysia

Bisseru B

Trop Geogr Med, 1970 Sep;22(3):352-6.
PMID: 5528459
Matched MeSH terms: Disease Vectors
Filariasis in Sabah, East Malaysia

Barclay R

Ann Trop Med Parasitol, 1969 Dec;63(4):473-88.
PMID: 4393668
Matched MeSH terms: Disease Vectors
Navigating parasite webs and parasite flow: emerging and re-emerging parasitic zoonoses of wildlife origin

Polley L

Int J Parasitol, 2005 Oct;35(11-12):1279-94.
PMID: 16168994

Wildlife are now recognised as an important source of emerging human pathogens, including parasites. This paper discusses the linkages between wildlife, people, zoonotic parasites and the ecosystems in which they co-exist, revisits definitions for 'emerging' and 're-emerging', and lists zoonotic parasites that can be acquired from wildlife including, for some, estimates of the associated global human health burdens. The paper also introduces the concepts of 'parasite webs' and 'parasite flow', provides a context for parasites, relative to other infectious agents, as causes of emerging human disease, and discusses drivers of disease emergence and re-emergence, especially changes in biodiversity and climate. Angiostrongylus cantonensis in the Caribbean and the southern United States, Baylisascaris procyonis in California and Georgia, Plasmodium knowlesi in Sarawak, Malaysia, Human African Trypanosomiasis, Sarcoptes scabiei in carnivores, and Cryptosporidium, Giardia and Toxoplasma in marine ecosystems are presented as examples of wildlife-derived zoonotic parasites of particular recent interest. An ecological approach to disease is promoted, as is a need for an increased profile for this approach in undergraduate and graduate education in the health sciences. Synergy among scientists and disciplines is identified as critical for the study of parasites and parasitic disease in wildlife populations. Recent advances in techniques for the investigation of parasite fauna of wildlife are presented and monitoring and surveillance systems for wildlife disease are discussed. Some of the limitations inherent in predictions for the emergence and re-emergence of infection and disease associated with zoonotic parasites of wildlife are identified. The importance of public awareness and public education in the prevention and control of emerging and re-emerging zoonotic infection and disease are emphasised. Finally, some thoughts for the future are presented.

Matched MeSH terms: Disease Vectors
Genetic diversity of zoonotic malaria parasites from mosquito vector and vertebrate hosts

Wong ML, Ahmed MA, Sulaiman WYW, Manin BO, Leong CS, Quan FS, et al.

Infect Genet Evol, 2019 09;73:26-32.
PMID: 30999059 DOI: 10.1016/j.meegid.2019.04.010

We explored and constructed haplotype network for simian malaria species: Plasmodium knowlesi, P. cynomolgi and P. inui aiming to understand the transmission dynamics between mosquitoes, humans and macaques. Mosquitoes were collected from villages in an area where zoonotic malaria is prevalent. PCR analysis confirmed Anopheles balabacensis as the main vector for macaque parasites, moreover nearly 60% of the mosquitoes harboured more than one Plasmodium species. Fragments of the A-type small subunit ribosomal RNA (SS rRNA) amplified from salivary gland sporozoites, and equivalent sequences obtained from GenBank were used to construct haplotype networks. The patterns were consistent with the presence of geographically distinct populations for P. inui and P. cynomolgi, and with three discrete P. knowlesi populations. This study provides a preliminary snapshot of the structure of these populations, that was insufficient to answer our aim. Thus, collection of parasites from their various hosts and over time, associated with a systematic analysis of a set of genetical loci is strongly advocated in order to obtain a clear picture of the parasite population and the flow between different hosts. This is important to devise measures that will minimise the risk of transmission to humans, because zoonotic malaria impedes malaria elimination.

Matched MeSH terms: Disease Vectors
Fulltext Paddy, piggy and Japanese encephalitis in Kerian – a case series

Rosilawati A. R., Mohd Zamri M. A.

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):40-40.
MyJurnal

Introduction: Japanese encephalitis (JE) is a vector-borne zoonotic disease caused by the Japanese encephalitis virus (JEV). Paddy fields are high risk area for JEV transmission due the presence of Culex tritaeniorhynchus as vector and wild boar as an amplifier host. Methods: We presented case reports for three patients infected with JEV residing in paddy field area from 2015 to 2018 in Kerian, Perak; illustrating the symptoms and epidemiology trend of the dis-ease. Results: All three cases live next to paddy field and were exposed during peak biting hours. They presented with fever and altered consciousness. IV Acylovir was started as one of the treatments and all had lumbar puncture for CSF testing. Two cases (adult) were confirmed JE after they had passed away. Two cases occurred during fasting month where food wastes were abundance. The source of infection was probably from wild boars that came out at night to hunt for food. Presence of C. tritaeniorhynchus was demonstrated as the main vector in these areas. Conclusion: JE has no cure and human vaccination is the main prevention method. At the moment, vector control, environmental management, chemical control and personal protection are the main mitigation strategies for this area. Further study on JEV and wild board in Kerian will be most beneficial.

Matched MeSH terms: Disease Vectors
Fulltext A systematic review: public health policies on Zika infection surveillance for Malaysia

Chin Mun Wong, Rozita Hod, Mohd Rohaizat Hassan, Sazaly Abu Bakar

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):3-3.
MyJurnal

Introduction: Zika infection was declared as Public Health Emergency of International Concern since year 2015. Despite of no new reported case via National Surveillance System for flavivirus, an underestimated seroprevalence might occur as the country contributes to the Asian lineage of the virus. Methods: Systematic literature search using PICO framework and PRISMA checklist across four databases for articles published from year 2013-2018 yielded 189 results, 37 articles accepted by titles following criteria were subjected to abstract screening, leaving 8 articles with clear risk proceed to full text analysis using Cochrane checklist and GRADE assessment. Results: There were four high quality articles and four low quality articles based on biases in studies. Blood product management and vac-cination are strategies strongly recommended to be implemented as Zika response while vector control and family planning are public health measures to be proposed as policy if feasible. Successful factors to improve Zika surveil-lance and management includes developing algorithm for blood product management, anti-Zika vaccine research, algorithm for new-born screening, participation of policy makers, healthcare capacity building, raising healthcare and public awareness on the infection, international funding, utilization of technology in data management and bio-logical control of vector. Conclusion: Implementation of Zika response as policy is timely, should be evidence-based and follow guidelines from WHO / CDC / FDA US after cost-effectiveness evaluation for Malaysia setting.

Matched MeSH terms: Disease Vectors
Fulltext Plasmodium-a brief introduction to the parasites causing human malaria and their basic biology

Sato S

J Physiol Anthropol, 2021 Jan 07;40(1):1.
PMID: 33413683 DOI: 10.1186/s40101-020-00251-9

Malaria is one of the most devastating infectious diseases of humans. It is problematic clinically and economically as it prevails in poorer countries and regions, strongly hindering socioeconomic development. The causative agents of malaria are unicellular protozoan parasites belonging to the genus Plasmodium. These parasites infect not only humans but also other vertebrates, from reptiles and birds to mammals. To date, over 200 species of Plasmodium have been formally described, and each species infects a certain range of hosts. Plasmodium species that naturally infect humans and cause malaria in large areas of the world are limited to five-P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi. The first four are specific for humans, while P. knowlesi is naturally maintained in macaque monkeys and causes zoonotic malaria widely in South East Asia. Transmission of Plasmodium species between vertebrate hosts depends on an insect vector, which is usually the mosquito. The vector is not just a carrier but the definitive host, where sexual reproduction of Plasmodium species occurs, and the parasite's development in the insect is essential for transmission to the next vertebrate host. The range of insect species that can support the critical development of Plasmodium depends on the individual parasite species, but all five Plasmodium species causing malaria in humans are transmitted exclusively by anopheline mosquitoes. Plasmodium species have remarkable genetic flexibility which lets them adapt to alterations in the environment, giving them the potential to quickly develop resistance to therapeutics such as antimalarials and to change host specificity. In this article, selected topics involving the Plasmodium species that cause malaria in humans are reviewed.

Matched MeSH terms: Disease Vectors

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