Plasmodium lineages

Inumaru, Mizue, Murata, Koichi & Sato, Yukita, 2017, Prevalence of avian haemosporidia among injured wild birds in Tokyo and environs, Japan, International Journal for Parasitology: Parasites and Wildlife 6 (3), pp. 299-309 : 304-305

4.3. Analysis of Plasmodium lineages

12 Plasmodium lineages were found in this study ( Table 3). Of these, 3 lineages were detected solely or mainly from wintering visitors. Plasmodium lineage SW5, classified as P. circum fl exum, and SW2, classified as P. homonucleophilum , have been recorded from various parts of the world and are thought to be transmitted by Culiseta spp. mosquitoes ( Meyer and Bennett, 1976; Valkiunas ¯, 2005; Ejiri et al., 2011a). Culiseta spp. are found in the holarctic ( Medvedev, 2009), but in Japan, the only known species ( C. kanayamensis and C. nipponica ) are found solely in Aomori and Hokkaido prefectures ( Ono, 1969; Ejiri et al., 2011b; Maekawa et al., 2016), the northern-most parts of Japan. Although there have been no reports of avian malaria from Culiseta spp. in Japan, Stellar's sea eagle ( Haliaeetus pelagicus ) and other bird DNA were detected from this mosquito genus ( Ejiri et al., 2011b). Also, in a previous study, SW5 was reported in Red-crowned crane ( Grus japonensis ) ( Yoshimura et al., 2014), a resident breeder that is found only in Hokkaido, Japan. Thus, the lineages SW 2 and SW5 might be transmitted in Northern Japan of further north. Interestingly, a new lineage FULATR01 found from Eurasian coot ( Fulica atra ) in this study was very close to SW2 (difference of only one base). If such difference is small enough to maintain the same lifecycle including vector species, this lineage may also only be transferred in the far north. Most individuals of Eurasian coot, which both FULATR01 and SW5 were detected, are wintering visitors in the Kanto region and breed in Northern Japan. However, there is a small population that breeds in the Kanto region ( Hashimoto and Sugawa, 2013). In the Kanto region, avian blood has been detected from infected mosquitoes, meaning that the host-vector-parasite lifecycle is preserved in this area ( Ejiri et al., 2009; Kim et al., 2009). We were not able to distinguish whether the individuals in this study were migratory or resident individuals, but due to the possible vector specificity of these lineages, there is a high possibility that the individuals in this study are migratory and were infected in areas further north. However, there is a possibility that there are vector species other than Culiseta spp. that are capable of transmitting these discussed species of Plasmodium . Further research is needed to justify this hypothesis. Of the high percentage of SW5 found in this study, the majority (5 of 8 individuals) were from Eurasian coot. Some lineages are known to have low host specificity and yet still have a high prevalence in a certain species ( Hellgren et al., 2009), which may be the case for this lineage.

4 lineages (PADOM02, SGS1, UPUPA 02 and YWT4) were found from resident breeders and have previously been reported from host species of other countries. SGS1 has been detected from vectors across many countries including 3 mosquito species ( Culex sasai , Cx. pipiens and Lutzia vorax ) in Japan and is known to have a wide vector, host and geographical range ( Tsuda, 2017). The vector species of the other 3 lineages have not been found in Japan, but also have a high chance that they may be wide-ranged lineages. The lineage CXPIP10 from Yellow bittern ( Ixobrychus sinensis ) was detected from an avian host for the first time. This lineage has been previously detected in Culex spp. of Spain and Japan ( Tsuda, 2017). Because of insufficient host information, the range of this lineage is unknown, but there is a high possibility that it is transmitted between vector and host in Japan.

2 lineages (CXPIP09 and CXPIP12) were found from resident breeders and have been previously detected from mosquito species in Japan ( Ejiri et al., 2009, 2011b; Kim and Tsuda, 2010). Large-billed crow ( Corvus macrorhynchos ) and Eurasian tree sparrow ( Passer montanus ) were detected from the blood-meal of CXPIP09-infected mosquitoes ( Kim and Tsuda, 2010) and this lineage made up over 21.4% of all the Plasmodium lineages found in this study. This highly suggests that this lineage is highly preserved among the avian hosts and mosquito vectors of Japan. These lineages have only been found in Japan, meaning that they are perhaps unique lineages of Japan. CXPIP09 was found from 1 Herring gull ( Larus argentatus ), a winter visitor species, which had been in the facility for 3 years. This strongly suggests that this individual was infected within the facility. Meanwhile, CXPIP12 had been detected in a previous study from Hawfinch ( Coccothraustes coccothraustes ), also a winter visitor. As the mosquito population density is known to decline in the Kanto area during the winter ( Kim and Tsuda, 2010), the chances of this species to get infected in the Kanto area are low. Hawfinch are known to breed as south as Nagano prefecture, a neighboring prefecture right next to the Kanto region ( Ornithological Society of Japan, 2012) and may have been infected in such areas. 1 new lineage NYCNYC02 was found in Black-crowned night-heron ( Nycticorax nycticorax ), which are mostly sedentary, but some individuals are known migrate to the Philippines (Yamashina Institute for Ornithology, 2002; Ornithological Society of Japan, 2012). Though these lineages may be unique lineages of Japan, the range of vector species such as Culex pipiens is very wide, including Russia ( Medvedev, 2009) and there is a significant exchange of birds between Japan and the surrounding continents, meaning there is a possibility that these lineages may be found in other areas of the world.