Bagaza virus and Plasmodium spp. coinfection in red-legged partridges ( Alectoris rufa ), in southern Spain 2019

Flaviviruses West Nile (WNV), Usutu (USUV) and Bagaza (BAGV) virus and avian malaria parasites are vector borne pathogens that circulate naturally between avian and mosquito hosts. WNV and USUV and potentially also BAGV constitute zoonoses. Temporal and spatial co-circulation and co-infection with Plasmodium spp., and West Nile virus has been documented in birds and mosquito vectors, and fatally USUV infected passerines coinfected with Plasmodium spp. had more severe lesions. Also, WNV, USUV and BAGV have been found to co-circulate. Yet little is known about the interaction of BAGV and malaria parasites during consecutive or co-infections of avian hosts. Here we report mortality of free-living red-legged partridges in a hunting estate in Southern Spain due to coinfection with BAGV and Plasmodium spp. The outbreak occurred in the area where BAGV first emerged in Europe in 2010 and where co-circulation of BAGV, USUV and WNV was confirmed in 2011 and 2013. Partridges were found dead in early October 2019. Birds had mottled locally pale pectoral muscles, enlarged, congestive greenish-black tinged livers and enlarged kidneys. Microscopically congestion and predominantly mononuclear inflammatory infiltrates were evident and Plasmodium phanerozoites were present in the liver, spleen, kidneys, muscle and skin. Molecular testing and sequencing detected Plasmodium spp. and BAGV in different tissues of the partridges, and immunohistochemistry confirmed the presence and co-localization of both pathogens in the liver and spleen. Although Plasmodium spp. are known to be highly prevalent in red-legged partridges, this is the first account of mortality caused by co-infection with BAGV and Plasmodium sp. Due to the importance of the red-legged partridge in the ecosystem of the Iberian Peninsula and as driver of regional economy such mortalities are of concern. Also, they may reflect climate change related changes in host, vector and pathogen ecology and interactions that could emerge similarly in other pathogens.

Survey on Avian Malaria Parasites in Village Chickens (Gallus gallus domesticus) in Gombe Local Government Area, Gombe State, Nigeria

Reports of avian malaria parasites in village chicken in Nigeria generally remain fragmentary and scarce. The study was conducted in Gombe Local Government Area of Gombe State, Nigeria to investigate avian malaria parasites in Village Chickens (Gallus gallus domesticus) and to determine the risk factors associated with the prevalence of the haemoparasites. A total of 530 village chickens blood samples were obtained from apparently healthy village chickens' brachial veins using sterile 2mls syringes and 23 gauge needles. Thin blood smear was made from each blood sample, and Giemsa stained and examined for the presence of avian haemoparasites under an electro-microscope. The result indicates 23.8% overall prevalence rate of three species of avian malaria parasites consisting of Plasmodium, Haemoproteus and Leucocytozoon species.Plasmodium spp. has the highest prevalent rate of 13.0% followed by Haemoproteus spp. (5.1%), mixed Plasmodium spp. + Haemoproteus spp. (4.9%) infection and Leucocytozoon spp. (0.8%). Prevalence of avian malaria parasites was significantly higher in cocks compared to hens (p < 0.05), as well as higher in adults compared to growers chickens (p < 0.05). This study also showed a higher prevalence of avian malaria parasites during the rainy season compared to the dry season of the study period. It was concluded that haemoparasites of Plasmodium, Haemoproteus and Leucocytozoon species that occur in both single and mixed infections are prevalent among village chickens that are apparently healthy in Gombe Local Government Area of Gombe State, Nigeria.

Zoonotic Transmission and Host Switches of Malaria Parasites

Malaria is a deadly disease that affects the health of hundreds of millions of people annually. Five Plasmodium parasite species naturally infect humans: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, and Plasmodium knowlesi. These parasites can also infect various non-human primates. Parasites mainly infecting monkeys, such as Plasmodium cynomolgi and P. knowlesi, the latter of which was considered to be a monkey parasite for years, can also be transmitted to human hosts. Recently, many new Plasmodium species have been discovered in African apes, some of which may be transmitted to humans in the future. Here, we searched PubMed and the internet via Google and selected articles on the zoonotic transmission and evolution of selected malaria parasite species. We review current advances in the relevant topics, emphasizing the transmission of malaria parasites between humans and non-human primates. We also briefly discuss the transmission of some avian malaria parasites between wild birds and domestic fowls. Zoonotic malaria transmission is widespread, thus posing a threat to public health. More studies on parasite species, including their identification in non-human primates, transmission, and evolution, are needed to decrease or prevent the transmission of malaria parasites from non-human primates to humans.

Plasmodium matutinum Transmitted by Culex pipiens as a Cause of Avian Malaria in Captive African Penguins (Spheniscus demersus) in Italy

Avian malaria is a parasitic disease of birds caused by protozoa belonging to the genus Plasmodium, within the order Haemosporida. Penguins are considered particularly susceptible, and outbreaks in captive populations can lead to high mortality. We used a multidisciplinary approach to investigate the death due to avian malaria, occurred between 2015 and 2019, in eight African penguins (Spheniscus demersus) kept in two Italian zoos located in central Italy, and situated about 30 km apart. We also provided information about the presence and circulation of Plasmodium spp. in mosquitoes in central Italy by sampling mosquitoes in both zoos where penguin mortalities occurred. In the eight dead penguins, gross and histopathological lesions were consistent with those previously observed by other authors in avian malaria outbreaks. Organs from dead penguins and mosquitoes collected in both zoos were tested for avian malaria parasites by using a PCR assay targeting the partial mitochondrial conserved region of the cytochrome b gene. Identification at species level was performed by sequencing analysis. Plasmodium matutinum was detected in both dead penguins and in mosquitoes (Culex pipiens), while Plasmodium vaughani in Culex pipiens only. Parasites were not found in any of the PCR tested Aedes albopictus samples. Based on our phylogenetic analysis, we detected three previously characterized lineages: Plasmodium matutinum LINN1 and AFTRU5, P. vaughani SYAT05. In Culex pipiens we also identified two novel lineages, CXPIP32 (inferred morphospecies Plasmodium matutinum) and CXPIP33 (inferred morphospecies P. vaughani). Significantly, LINN1 and AFTRU5 were found to be associated to penguin deaths, although only LINN1 was detected both in penguins (along the years of the study) and in Culex pipiens, while AFTRU5 was detected in a single penguin dead in 2017. In conclusion, in our study Plasmodium matutinum was found to cause avian malaria in captive penguins kept in Europe, with Culex pipiens being its most probable vector. Our results are in agreement with previous studies suggesting that Culex pipiens is one of the main vectors of Plasmodium spp. in Europe and the Northern Hemisphere. Zoos maintaining captive penguins in temperate areas where Culex pipiens is abundant should be well aware of the risks of avian malaria, and should put every effort to prevent outbreaks, in particular during the periods when the number of vectors is higher.

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

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.

Assessing Diversity, Plasmodium Infection and Blood Meal Sources in Mosquitoes (Diptera: Culicidae) from a Brazilian Zoological Park with Avian Malaria Transmission

Avian malaria parasites are widespread parasites transmitted by Culicidae insects belonging to different genera. Even though several studies have been conducted recently, there is still a lack of information about potential vectors of Plasmodium parasites, especially in Neotropical regions. Former studies with free-living and captive animals in São Paulo Zoo showed the presence of several Plasmodium and Haemoproteus species. In 2015, a pilot study was conducted at the zoo to collect mosquitoes in order to find out (i) which species of Culicidae are present in the study area, (ii) what are their blood meal sources, and (iii) to which Plasmodium species might they be potential vectors. Mosquitoes were morphologically and molecularly identified. Blood meal source and haemosporidian DNA were identified using molecular protocols. A total of 25 Culicidae species were identified, and 6 of them were positive for Plasmodium/Haemoproteus DNA. Ten mosquito species had their source of blood meal identified, which were mainly birds, including some species that were positive for haemosporidian parasites in the former study mentioned. This study allowed us to expand the list of potential vectors of avian malaria parasites and to improve our knowledge of the evolutionary and ecological relationships between the highly diverse communities of birds, parasites, and vectors present at São Paulo Zoo.

No evidence that songbirds use odour cues to avoid malaria-infected conspecifics

Many animals have evolved mechanisms to detect and avoid parasitized conspecifics, primarily through odour cues, but whether birds are capable of odour-mediated parasite avoidance is unknown. Recently, we showed that exposing song sparrows (Melospiza melodia) to avian malaria parasites (Plasmodium sp.) alters the chemical composition of their preen oil, which is the major source of body odour in birds. Here, we presented song sparrows with preen oil from uninfected (sham-inoculated) and malaria-infected conspecifics, predicting that birds would spend more time with odour cues from uninfected than infected birds. Birds without detectable malarial infections spent about 50% more time with preen oil from uninfected than infected conspecifics, and females spent nearly twice as much time with preen oil from uninfected than infected conspecifics. However, neither difference was statistically significant. Song sparrows may be able to detect odour cues of infection, but further experiments are needed to confirm or refute this.