Sporogony and sporozoite rates of avian malaria parasites in wild Culex pipiens pallens and C. inatomii in Japan

Kim, Kyeong-Soon; Tsuda, Yuichi

doi:10.1186/s13071-015-1251-1

Cited by 17 publications

(10 citation statements)

References 25 publications

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“…Both sporozoites and oocysts of CXPIP09 have been confirmed in Cx. pipiens group, verifying that this mosquito species is a competent vector [ 5 ]. This lineage was detected from mosquitoes in all sampling years, strongly suggesting that this lineage is maintained at the study site.…”

Section: Discussionmentioning

confidence: 99%

“…As part of conservation efforts, ex-situ populations have been established in zoos, aquariums and other breeding facilities throughout the world. Avian malaria, caused by Plasmodium parasites, is mainly transmitted by Culex mosquitoes [ 2 – 5 ]. Due to their evolutionary background in environments of little contact with vector species, penguins are mostly naïve to avian malaria and many lethal cases of avian malarial infections have been reported in captive penguins [ 6 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

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Vector incrimination and transmission of avian malaria at an aquarium in Japan: mismatch in parasite composition between mosquitoes and penguins

Inumaru

Yamada

Shimizu

et al. 2021

Malar J

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Background Captive populations of penguins outside of their natural distributions are often maintained in outdoor facilities, such as zoos and aquariums. Consequently, such penguins in captivity are constantly exposed to mosquito vectors and risk of avian malarial infection during their active period from spring to autumn, which can be lethal to these naïve birds. Previous studies have investigated parasite prevalence in mosquitoes or penguins, but simultaneous investigations, which would be crucial to monitor the transmission dynamics and cycle within a facility, have not been done. To identify dominant lineages and trends, multiple-year surveys are recommended. Methods Avian malaria parasites (Plasmodium spp.) and related haemosporidia were tested in penguins and mosquitoes at an aquarium in Japan through multiple years from 2011 to 2018. Prevalence and dynamics were confirmed, and molecular analyses targeting the protozoal cytb gene were used to reveal the transmission cycle. Blood meals of mosquitoes were also identified using molecular methods. Results Parasite detection in penguins tended to fluctuate within an individual. Two Plasmodium lineages were consistently detected in mosquitoes that had fed on penguins and wild birds observed around the aquarium. Plasmodium lineage CXPIP09 was detected from both mosquitoes and penguins, suggesting active transmission at this facility. However, Plasmodium cathemerium PADOM02 was only detected in mosquitoes, which may be due to host, vector or parasite-related factors, or detection methods and their limits. Additionally, Haemoproteus larae SPMAG12 was detected from penguins, suggesting active transmission via biting midges. Conclusions The mismatch in parasite composition between penguins and mosquitoes shows that multiple aspects such as captive birds, wild birds and vector insects should be monitored in order to better understand and control avian malarial infection within ex-situ conservation facilities. Furthermore, morphological analyses would be needed to confirm competency and infection dynamics of avian malaria parasites.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Vector incrimination and transmission of avian malaria at an aquarium in Japan: mismatch in parasite composition between mosquitoes and penguins

Inumaru

Yamada

Shimizu

et al. 2021

Malar J

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“…pseudotitillans , suggesting that these species are potential vectors of avian malaria parasites in the SDTF of Brazil. However, detection of Plasmodium DNA using molecular methods alone does not confirm transmission; one must also visualize sporozoites in the salivary glands of mosquitoes using microscopy or should conduct experimental infections to confirm true vector identity [38, 39]. Nevertheless, our study represents an important step in identifying vectors of avian malaria parasites in the Neotropics.…”

Section: Discussionmentioning

confidence: 99%

“…Avian malaria vectors can have negative thoraces when corresponding abdomens are positive in experimental and natural conditions [39, 45, 49]. For example, detection of positive thoraces by PCR starts at nine days after experimental infections of competent vectors, with positivity rates varying from 22.2 to 60% afterwards [45].…”

Section: Discussionmentioning

confidence: 99%

Searching for putative avian malaria vectors in a Seasonally Dry Tropical Forest in Brazil

et al. 2016

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BackgroundHaemosporidian parasites of the genera Plasmodium and Haemoproteus can have detrimental effects on individual birds and populations. Despite recent investigations into the distribution and richness of these parasites and their vertebrate hosts, little is known about their dipteran vectors. The Neotropics has the highest diversity of mosquitoes in the world, but few studies have tried to identify vectors in this area, hampering the understanding of the ecology of avian malaria in the highly diverse Neotropical environments.MethodsShannon traps and active collection were used to capture 27,110 mosquitoes in a Seasonally Dry Tropical Forest in southeastern Brazil, a highly endangered ecosystem.ResultsWe screened 17,619 mosquito abdomens from 12 different species and several unidentified specimens of Culex, grouped into 1,913 pools, for the presence of haemosporidians. Two pools (out of 459) of the mosquito Mansonia titillans and one pool (out of 29) of Mansonia pseudotitillans were positive for Plasmodium parasites, with the detection of a new parasite lineage in the former species. Detected Plasmodium lineages were distributed in three different clades within the phylogenetic tree revealing that Mansonia mosquitoes are potential vectors of genetically distant parasites. Two pools of Culex spp. (out of 43) were positive for Plasmodium gallinaceum and closely related lineages. We found a higher abundance of these putative vectors in pasture areas, but they were also distributed in areas at intermediate and late successional stages. One pool of the mosquito Psorophora discrucians (out of 173) was positive for Haemoproteus.ConclusionsThe occurrence of different Plasmodium lineages in Mansonia mosquitoes indicates that this genus encompasses potential vectors of avian malaria parasites in Brazil, even though we did not find positive thoraces among the samples tested. Additional evidence is required to assign the role of Mansonia mosquitoes in avian malaria transmission and further studies will add information about evolutionary and ecological aspects of avian haemosporidia and untangle the diversity of their vectors in Brazil.

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“…Species in the Culex pipiens complex are world widely distributed [4,30,31], meanwhile important vectors to plenty of virus and parasites, including West Nile virus, Wuchereria bancrofti and Diro laria immitis [29,32,33]. Culex pipiens pallens, commonly found north of 37°N in China, Japan and Korea, is one of the major mosquito species natively responsible for biting human and disease transmission [34].…”

Section: Introductionmentioning

confidence: 99%

Coagulation-Flocculation: A potential Application for Mosquito Larval Source Management (LSM) with No Insecticide Resistance

Li¹,

Huang²,

PeiEn³

et al. 2020

Preprint

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Background: Mosquito control is an essential step to eliminate mosquito-borne diseases. Larval mosquitoes have a more limited home range and lower resistance to adverse environment than adults, thus can be ideal targets for vector control in some cases. Coagulation-flocculation technology, which could be used for water treatment in breeding sites of several vector mosquito species, can significantly change both the distribution of organic particles and surface sediment characteristics in water environment. The aim of this study was to explore the effect, principle and possibility of using coagulation-flocculation technology in immature mosquitoes killing.Method: In laboratory, chlorine-free tap water was treated with Poly Aluminum Chloride (PACl, sewage treatment using). The oviposition preference of gravid Culex pipiens pallens, the hatching of mosquito eggs and the survival amount of mosquito larvae were observed, and the pupa amounts were recorded each day.Results: Coagulation-flocculation treatment could improve the oviposition preference of Culex pipiens pallens to some extent (compared with ordinary chlorine-free tap water), but not significantly (p=0.345). After treatment, mosquitoes laid eggs in chlorine-free tap water were 31.88% more than those laid in untreated water. Coagulation-flocculation affected the larvae’s survival by physical means: Ⅰ) alum floc layer increases the difficulty of larvae foraging, leads larvae starving to death; (Ⅱ) the little floc particles adhere to the surface of larvae, which stops larvae from floating upward to breathe. As a result, the alum floc layer had a good killing effect on the mosquito larvae, presented the half lethal time (LT50) of 2d, the 90% lethal time (LT90) of 8.7±7.3 ~ 14±4.5 d, and the pupation rate of 0 ~ (6.5±0.5)%, respectively.Conclusions: PACl coagulation-flocculation produced lots of alum flocs, which may attract more gravid mosquitoes for laying eggs, and was shown to be highly active against 1st~2nd instar larvae. The principle of this technology illustrates this method won’t develop insecticide resistance. In this study, coagulation-flocculation technology is considered to be a new potential approach to a sustainable, low-impact and low-cost mosquito control method.

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Sporogony and sporozoite rates of avian malaria parasites in wild Culex pipiens pallens and C. inatomii in Japan

Cited by 17 publications

References 25 publications

Vector incrimination and transmission of avian malaria at an aquarium in Japan: mismatch in parasite composition between mosquitoes and penguins

Vector incrimination and transmission of avian malaria at an aquarium in Japan: mismatch in parasite composition between mosquitoes and penguins

Searching for putative avian malaria vectors in a Seasonally Dry Tropical Forest in Brazil

Coagulation-Flocculation: A potential Application for Mosquito Larval Source Management (LSM) with No Insecticide Resistance

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