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Plasmodium knowlesi: the emerging zoonotic malaria parasite

Antinori S, Galimberti L, Milazzo L, Corbellino M

Acta Trop, 2013 Feb;125(2):191-201.
PMID: 23088834 DOI: 10.1016/j.actatropica.2012.10.008

Plasmodium knowlesi was initially identified in the 30s as a natural Plasmodium of Macaca fascicularis monkey also capable of experimentally infecting humans. It gained a relative notoriety in the mid-30s as an alternative to Plasmodium vivax in the treatment of the general paralysis of the insane (neurosyphilis). In 1965 the first natural human infection was described in a US military surveyor coming back from the Pahang jungle of the Malaysian peninsula. P. knowlesi was again brought to the attention of the medical community when in 2004, Balbir Singh and his co-workers reported that about 58% of malaria cases observed in the Kapit district of the Malaysian Borneo were actually caused by P. knowlesi. In the following years several reports showed that P. knowlesi is much more widespread than initially thought with cases reported across Southeast Asia. This infection should also be considered in the differential diagnosis of any febrile travellers coming back from a recent travel to forested areas of Southeast Asia. P. knowlesi can cause severe malaria with a rate of 6-9% and with a case fatality rate of 3%. Respiratory distress, acute renal failure, shock and hyperbilirubinemia are the most frequently observed complications of severe P. knowlesi malaria. Chloroquine is considered the treatment of choice of uncomplicated malaria caused by P. knowlesi.

Matched MeSH terms: Anopheles/parasitology
Molecular identification of Anopheles (Cellia) sundaicus from the Andaman and Nicobar islands of India

Alam MT, Das MK, Ansari MA, Sharma YD

Acta Trop, 2006 Jan;97(1):10-8.
PMID: 16125659

Anopheles (Cellia) sundaicus (Rodenwaldt) is an important malaria vector in the Andaman and Nicobar islands of India where it breeds in freshwater as well as in brackish water. To establish the molecular identity of An. sundaicus on these islands we analyzed samples from four geographically isolated areas-Teressa, Nancowry, Car Nicobar and Katchal islands. PCR-amplification and nucleotide sequence analysis were performed for internal transcribed spacer 2 (ITS2) and domain-3 (D3) of 28S rRNA. The ITS2 region of An. sundaicus from all four islands was identical but different from An. sundaicus A of Vietnam and An. sundaicus s.s of Malaysia. Furthermore, freshwater and brackish water forms of An. sundaicus did not reveal any sequence variation. Similarly, the D3 sequences were identical among all An. sundaicus samples from the four islands. D3 sequences for a species of the Sundaicus Complex are reported here for the first time and thus could not be compared with other regional isolates of this species. In conclusion, probably only one member of the Sundaicus Complex exists on the Andaman and Nicobar islands, which breeds in freshwater as well as in brackish water and is different from the An. sundaicus A and Malaysian An. sundaicus s.s. The identification of a new sibling species of the Sundaicus Complex in these islands is significant from the viewpoint of vector control strategies.

Matched MeSH terms: Anopheles/classification*; Anopheles/genetics
The impact of development and malaria control activities on its vectors in the Kinabatangan area of Sabah, East Malaysia

Vythilingam I, Chan ST, Shanmugratnam C, Tanrang H, Chooi KH

Acta Trop, 2005 Oct;96(1):24-30.
PMID: 16076459

A study was carried out from July 2001 until January 2003 in the Kinabatangan area of Sabah, part of Borneo island, where malaria used to be mesoendemic. Vector surveys determined that Plasmodium falciparum was the predominant species and Anopheles balabacensis the primary vector. Malaria cases have dropped drastically over the years but P. falciparum is still predominant. In the present study, Anopheles donaldi was the predominant species and was positive for sporozoites. Although An. balabacensis was present, none were infective. An. donaldi bite more outdoors than indoors and have a peak biting time from 18:00 to 19:00 h when most people are still out of their homes. An integrated malaria control programme along with area development has helped in the control of malaria and its vector.

Matched MeSH terms: Anopheles/classification; Anopheles/parasitology*
Seasonality of Anopheles aconitus mosquitoes, a secondary vector of malaria, in an endemic village near the Malaysia-Thailand border

Rahman WA, Abu Hassan A, Adanan CR

Acta Trop, 1993 Dec;55(4):263-5.
PMID: 8147283
Matched MeSH terms: Anopheles*
The prevalence of Plasmodium falciparum and P. vivax in relation to Anopheles maculatus densities in a Malaysian village

Rahman WA, Abu Hassan A, Adanan CR, Rashid MR

Acta Trop, 1993 Dec;55(4):231-5.
PMID: 8147279

Blood from most of the residents of a remote village in northern peninsular Malaysia, bordering Thailand, was examined for malaria parasites monthly for 1 year. Plasmodium vivax was the commonest infection, but P. falciparum and mixed infections also occurred. Monthly collections of the malaria vector, Anopheles maculatus showed a positive correlation between mosquito densities and malaria positivity in the human population and a negative correlation with rainfall.

Matched MeSH terms: Anopheles*
Engineering and malaria control: learning from the past 100 years

Konradsen F, van der Hoek W, Amerasinghe FP, Mutero C, Boelee E

Acta Trop, 2004 Jan;89(2):99-108.
PMID: 14732233

Traditionally, engineering and environment-based interventions have contributed to the prevention of malaria in Asia. However, with the introduction of DDT and other potent insecticides, chemical control became the dominating strategy. The renewed interest in environmental-management-based approaches for the control of malaria vectors follows the rapid development of resistance by mosquitoes to the widely used insecticides, the increasing cost of developing new chemicals, logistical constraints involved in the implementation of residual-spraying programs and the environmental concerns linked to the use of persistent organic pollutants. To guide future research and operational agendas focusing on environmental-control interventions, it is necessary to learn from the successes and failures from the time before the introduction of insecticides. The objective of this paper is to describe the experiences gained in Asia with early vector control interventions focusing on cases from the former Indian Punjab, Malaysia and Sri Lanka. The paper deals primarily with the agricultural engineering and land and water management vector control interventions implemented in the period 1900-1950. The selected cases are discussed in the wider context of environment-based approaches for the control of malaria vectors, including current relevance. Clearly, some of the interventions piloted and implemented early in the last century still have relevance today but generally in a very site-specific manner and in combination with other preventive and curative activities. Some of the approaches followed earlier on to support implementation would not be acceptable or feasible today, from a social or environmental point of view.

Matched MeSH terms: Anopheles/parasitology
A mark-release-recapture experiment with Anopheles lesteri paraliae in northwest Peninsular Malaysia

Jaal Z, MacDonald WW

Ann Trop Med Parasitol, 1992 Aug;86(4):419-24.
PMID: 1463364

In a coastal village in northwest Malaysia, 3231 fed Anopheles females of eight to 10 species were collected, marked with fluorescent dust, and released on three consecutive nights. In collections made on the 10 nights after the first release, 58 mosquitoes of three species, An. lesteri paraliae, An. subpictus and An. vagus, were recaptured; the recapture rates were 3.42%, 1.19% and 0.97%, respectively. The data for An. subpictus and An. vagus were insufficient for further analysis. Those for An. l. paraliae were plotted against time of recapture and, from the regression coefficient, an estimate of 0.68 was obtained for the daily survival rate. An independent estimate based on the parous rate during the previous year was 0.55. The temporal distribution of the recaptures strongly suggested a gonotrophic cycle and oviposition cycle of two days.

Matched MeSH terms: Anopheles/anatomy & histology; Anopheles/physiology*
Transmission dynamics and estimates of malaria vectorial capacity for Anopheles balabacensis and An. flavirostris (Diptera: Culicidae) on Banggi island, Sabah, Malaysia

Hii JL, Kan S, Vun YS, Chin KF, Tambakau S, Chan MK, et al.

Ann Trop Med Parasitol, 1988 Feb;82(1):91-101.
PMID: 3041932

Holoendemic malaria transmission in two small isolated forest communities and a coastal village was studied by (1) all night human bait collections of Anopheles species from inside and outside houses and (2) buffalo-biting and CDC light-trapping catches during March and November 1984. During the same period thick and thin blood films were collected from the human population, and spleen rates were determined in children from two to nine years of age. Using both the immunoradiometric assay (IRMA) and the dissection technique, more sporozoite-positive infections were detected in An. balabacensis and An. flavirostris in November than in March. IRMA confirmed the presence of Plasmodium falciparum sporozoites. An average of 76.2% of the An. balabacensis population lived long enough to have reached a point where infectivity with P. falciparum was possible in November. Although fewer than five adult females bit humans per night at any time, a resident could theoretically have received more than 160 infective bites in one year. A high frequency of feeding on humans, coupled with increased anopheline life expectancy, contributed to high estimates of falciparum malaria vectorial capacity (number of infections distributed per case per day); for An. balabacensis (1.44-7.44 in March and 9.97-19.7 in November) and for An. flavirostris (0.19-5.14 in March and 6.27-15.8 in November). These high values may explain the increased malaria parasite rates obtained from at least two forest communities. Correlation between actual and calculated rates of gametocytaemia was poorest in Kapitangan due to inadequate sampling of the human population. In Banggi island, malaria is stable and holoendemic, and the population enjoys a high degree of immunity.

Matched MeSH terms: Anopheles/parasitology*
Arbovirus infections in Sarawak, October 1968--February 1970: Japanese encephalitis virus isolations from mosquitoes

Simpson DI, Bowen ET, Way HJ, Platt GS, Hill MN, Kamath S, et al.

Ann Trop Med Parasitol, 1974 Dec;68(4):393-404.
PMID: 4155608
Matched MeSH terms: Anopheles/microbiology
Anopheline mosquitoes as vectors of animal malaria in Malaya

REID JA, WEITZ B

Ann Trop Med Parasitol, 1961 Jul;55:180-6.
PMID: 13740488
Matched MeSH terms: Anopheles*
A REVISION OF THE ANOPHELES AITKENII GROUP IN MALAYA AND BORNEO

REID JA

Ann Trop Med Parasitol, 1965 Mar;59:106-25.
PMID: 14297346
Matched MeSH terms: Anopheles*
STUDIES TO DETERMINE THE VECTORS OF MONKEY MALARIA IN MALAYA

WHARTON RH, EYLES DE, WARREN M, CHEONG WH

Ann Trop Med Parasitol, 1964 Mar;58:56-77.
PMID: 14147666
Matched MeSH terms: Anopheles*
STUDIES ON THE DISTRIBUTION AND TRANSMISSION OF MALARIA AND FILARIASIS AMONG ABORIGINES IN MALAYA

WHARTON RH, LAING AB, CHEONG WH

Ann Trop Med Parasitol, 1963 Jun;57:235-54.
PMID: 14042655
Matched MeSH terms: Anopheles*
Notes on anopheline mosquitoes from Malaya, with descriptions of three new species

REID JA

Ann Trop Med Parasitol, 1963 Mar;57:97-116.
PMID: 13973755
Matched MeSH terms: Anopheles*
Fulltext The cry toxin operon of Clostridium bifermentans subsp. malaysia is highly toxic to Aedes Larval Mosquitoes

Qureshi N, Chawla S, Likitvivatanavong S, Lee HL, Gill SS

Appl Environ Microbiol, 2014 Sep;80(18):5689-97.
PMID: 25002432 DOI: 10.1128/AEM.01139-14

The management and control of mosquito vectors of human disease currently rely primarily on chemical insecticides. However, larvicidal treatments can be effective, and if based on biological insecticides, they can also ameliorate the risk posed to human health by chemical insecticides. The aerobic bacteria Bacillus thuringiensis and Lysinibacillus sphaericus have been used for vector control for a number of decades. But a more cost-effective use would be an anaerobic bacterium because of the ease with which these can be cultured. More recently, the anaerobic bacterium Clostridium bifermentans subsp. malaysia has been reported to have high mosquitocidal activity, and a number of proteins were identified as potentially mosquitocidal. However, the cloned proteins showed no mosquitocidal activity. We show here that four toxins encoded by the Cry operon, Cry16A, Cry17A, Cbm17.1, and Cbm17.2, are all required for toxicity, and these toxins collectively show remarkable selectivity for Aedes rather than Anopheles mosquitoes, even though C. bifermentans subsp. malaysia is more toxic to Anopheles. Hence, toxins that target Anopheles are different from those expressed by the Cry operon.

Matched MeSH terms: Anopheles/drug effects; Anopheles/physiology
Green-synthesized CdS nano-pesticides: Toxicity on young instars of malaria vectors and impact on enzymatic activities of the non-target mud crab Scylla serrata

Sujitha V, Murugan K, Dinesh D, Pandiyan A, Aruliah R, Hwang JS, et al.

Aquat Toxicol, 2017 Jul;188:100-108.
PMID: 28482328 DOI: 10.1016/j.aquatox.2017.04.015

Currently, nano-formulated mosquito larvicides have been widely proposed to control young instars of malaria vector populations. However, the fate of nanoparticles in the aquatic environment is scarcely known, with special reference to the impact of nanoparticles on enzymatic activity of non-target aquatic invertebrates. In this study, we synthesized CdS nanoparticles using a green protocol relying on the cheap extract of Valoniopsis pachynema algae. CdS nanoparticles showed high toxicity on young instars of the malaria vectors Anopheles stephensi and A. sundaicus. The antimalarial activity of the nano-synthesized product against chloroquine-resistant (CQ-r) Plasmodium falciparum parasites was investigated. From a non-target perspective, we focused on the impact of this novel nano-pesticide on antioxidant enzymes acetylcholinesterase (AChE) and glutathione S-transferase (GST) activities of the mud crab Scylla serrata. The characterization of nanomaterials was carried out by UV-vis and FTIR spectroscopy, as well as SEM and XRD analyses. In mosquitocidal assays, LC50 of V. pachynema-synthesized CdS nanoparticles on A. stephensi ranged from 16.856 (larva I), to 30.301μg/ml (pupa), while for An. sundaicus they ranged from 13.584 to 22.496μg/ml. The antiplasmodial activity of V. pachynema extract and CdS nanoparticles was evaluated against CQ-r and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of V. pachynema extract was 58.1μg/ml (CQ-s) and 71.46μg/ml (CQ-r), while nano-CdS IC50 was 76.14μg/ml (CQ-s) and 89.21μg/ml (CQ-r). In enzymatic assays, S. serrata crabs were exposed to sub-lethal concentrations, i.e. 4, 6 and 8μg/ml of CdS nanoparticles, assessing changes in GST and AChE activity after 16days. We observed significantly higher activity of GST, if compared to the control, during the whole experiment period. In addition, a single treatment with CdS nanoparticles led to a significant decrease in AChE activity over time. The toxicity of CdS nanoparticles and Cd ions in aqueous solution was also assessed in mud crabs, showing higher toxicity of aqueous Cd ions if compared to nano-CdS. Overall, our results underlined the efficacy of green-synthesized CdS nanoparticles in malaria vector control, outlining also significant impacts on the enzymatic activity of non-target aquatic organisms, with special reference to mud crabs.

Matched MeSH terms: Anopheles/drug effects
Quantitative trait loci in Anopheles gambiae controlling the encapsulation response against Plasmodium cynomolgi Ceylon

Zheng L, Wang S, Romans P, Zhao H, Luna C, Benedict MQ

BMC Genet, 2003 Oct 24;4:16.
PMID: 14577840

Anopheles gambiae females are the world's most successful vectors of human malaria. However, a fraction of these mosquitoes is refractory to Plasmodium development. L3-5, a laboratory selected refractory strain, encapsulates transforming ookinetes/early oocysts of a wide variety of Plasmodium species. Previous studies on these mosquitoes showed that one major (Pen1) and two minor (Pen2, Pen3) autosomal dominant quantitative trait loci (QTLs) control the melanotic encapsulation response against P. cynomolgi B, a simian malaria originating in Malaysia.

Matched MeSH terms: Anopheles/genetics*; Anopheles/parasitology
Fulltext Factors that are associated with the risk of acquiring Plasmodium knowlesi malaria in Sabah, Malaysia: a case-control study protocol

Grigg MJ, William T, Drakeley CJ, Jelip J, von Seidlein L, Barber BE, et al.

BMJ Open, 2014 Aug 22;4(8):e006004.
PMID: 25149186 DOI: 10.1136/bmjopen-2014-006004

INTRODUCTION: Plasmodium knowlesi has long been present in Malaysia, and is now an emerging cause of zoonotic human malaria. Cases have been confirmed throughout South-East Asia where the ranges of its natural macaque hosts and Anopheles leucosphyrus group vectors overlap. The majority of cases are from Eastern Malaysia, with increasing total public health notifications despite a concurrent reduction in Plasmodium falciparum and P. vivax malaria. The public health implications are concerning given P. knowlesi has the highest risk of severe and fatal disease of all Plasmodium spp in Malaysia. Current patterns of risk and disease vary based on vector type and competence, with individual exposure risks related to forest and forest-edge activities still poorly defined. Clustering of cases has not yet been systematically evaluated despite reports of peri-domestic transmission and known vector competence for human-to-human transmission.
METHODS AND ANALYSIS: A population-based case-control study will be conducted over a 2-year period at two adjacent districts in north-west Sabah, Malaysia. Confirmed malaria cases presenting to the district hospital sites meeting relevant inclusion criteria will be requested to enrol. Three community controls matched to the same village as the case will be selected randomly. Study procedures will include blood sampling and administration of household and individual questionnaires to evaluate potential exposure risks associated with acquisition of P. knowlesi malaria. Secondary outcomes will include differences in exposure variables between P. knowlesi and other Plasmodium spp, risk of severe P. knowlesi malaria, and evaluation of P. knowlesi case clustering. Primary analysis will be per protocol, with adjusted ORs for exposure risks between cases and controls calculated using conditional multiple logistic regression models.
ETHICS: This study has been approved by the human research ethics committees of Malaysia, the Menzies School of Health Research, Australia, and the London School of Hygiene and Tropical Medicine, UK.

Matched MeSH terms: Anopheles
Fulltext Host and environmental factors that influence Plasmodiu Knowlesi Mamlaria infection in humans: a systematic review

Michal Christina Steven

Borneo Epidemiology Journal, 2020;1(2):104-115.
MyJurnal

Introduction:Plasmodium knowlesi(P.knowlesi) is a zoonotic malaria parasite, transmitted between non-factors” or “individual factors” or “ecological factors” and “P.knowlesi” and “human” including human primate hosts by the Anopheles (An.) mosquitos, and causing spill-over infections in humans where the parasite, vector, host, and human converge
Methods:The search was done electronically toexplore for appropriate papers viaPubMed, and Science Direct for articles published up to March 2020, containing the words “factors associated” or “environmental synonyms and Medical Subject Heading (MeSH) terms. A total of 27 articles from PubMed Databases and 18 articles from Science Direct were selected to be assessed for eligibility. Out of it, a total of 13 articles were selected to be analysed.
Results:Host factors such as sex and age, as well as occupation as individual factors, while environmental factors such as rainfall and geographic elevation have some association with P.knowlesiinfection in humans. This zoonotic malaria poses unique challenges that will need to be addressed if all forms of malaria are to be eliminated based on the sustainable development goal (SDG)
Conclusion:This article highlights the importance of disease ecologies such as climate and landscape and human-environment interactions such as the land use patterns, such as agriculture or infrastructure activities) to reduce the further increase of cases and mortality globally due to P.knowlesiinfection. This review focuses mainly on the host and environmental factors that influence P.knowlesiMalaria Infection in Humans

Matched MeSH terms: Anopheles
A summary of records of Anopheline breeding places in Malaya

Gater BAR, Rajamoney PD

Bull Inst Med Res Kuala Lumpur, 1929.

Matched MeSH terms: Anopheles

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