Modeling the population impacts of avian malaria on Hawaiian honeycreepers: Bifurcation analysis and implications for conservation

Global prevalence of Plasmodium infection in wild birds: A systematic review and meta-analysis

Avian malaria is a vector-borne parasitic disease caused by Plasmodium infection transmitted to birds by mosquitoes. The aim of this systematic review was to analyze the global prevalence of malaria and risk factors associated with infection in wild birds. A systematic search of the databases CNKI, WanFang, VIP, PubMed, and ScienceDirect was performed from database inception to 24 February 2023. The search identified 3181 retrieved articles, of which 52 articles met predetermined inclusion criteria. Meta-analysis was performed using the random-effects model. The estimated pooled global prevalence of Plasmodium infection in wild birds was 16%. Sub-group analysis showed that the highest prevalence was associated with adult birds, migrant birds, North America, tropical rainforest climate, birds captured by mist nets, detection of infection by microscopy, medium quality studies, and studies published after 2016. Our study highlights the need for more understanding of Plasmodium prevalence in wild birds and identifying risk factors associated with infection to inform future infection control measures.

Global dynamics and bifurcation analysis of an insect-borne plant disease model with two transmission routes

Huanglongbing (HLB) is a plant disease mainly spread by the insect-borne citrus psyllid. It is the most destructive citrus pathosystem worldwide. To understand the impact of sexual transmission on HLB dynamics, we propose a host–vector–HLB compartment model incorporating two transmission routes. The basic reproduction number [Formula: see text] is derived. Various interventions of the disease are assessed. We also investigate the effect of different incidence functions to simulate sexual transmission. For the case of sublinear incidence functions, the disease-free equilibrium is globally asymptotically stable (GAS) provided [Formula: see text]. For mass action incidence of sexual transmission, the endemic equilibrium is GAS provided [Formula: see text]. However, under nonlinear incidence, it is proved that the model may exhibit backward bifurcation. Theoretical and numerical studies reveal that (i) different forces of infection between heterosexual psyllids in the model may have a distinct impact on disease dynamics; (ii) sensitivity analysis shows that for [Formula: see text], the transmission rate between host and vector is more sensitive parameter than that between heterosexual psyllids; (iii) if the sexual transmission is ignored, the disease burden is likely to be underestimated in comparison with realistic scenarios; (iv) in the absence of chemical insecticides, the combined use of yellow sticky traps and injection of nutrient solutions can be more effective in suppressing the spread of HLB. These findings provide valuable insights for public policymakers to determine the long-term viability of implemented HLB management strategies and highlight the urgency of finding sustainable HLB solutions.

Blood parasites of bird communities in Sri Lanka and their mosquito vectors

Avian blood parasites have been shown to have significant health effects on avifauna worldwide. Sri Lanka, a tropical island rich with resident and migratory birds, has not been properly evaluated for avian blood parasites or their vectors. We investigated the presence of avian haemoparasites in Sri Lankan birds and the potential mosquito vectors of those pathogens. Blood samples were collected from local/migratory birds captured by standard mist nets from Anawilundawa bird sanctuary, Hanthana mountain range, and the University of Peradeniya park. Mosquitoes were collected from Halgolla forest reserve and the forest patches in Kurunegala and Gampola areas in addition to the above mist-netting localities. Part of the mitochondrial cytochrome b (cytb) gene was amplified and sequenced to detect the presence of haemoparasites from avian blood samples (86) and mosquito samples (480). Blood parasites of the two genera, i.e., Haemoproteus (4 species; Haemoproteus sp. 1-4) and Plasmodium (5 species; Plasmodium sp. 1-5) were identified from seven bird species (four resident and three migratory). Among these, three bird species (Red-vented bulbul (3/16), Asian Brown flycatcher (1/1), and India pitta (1/1)) were positive for Plasmodium spp., while four (Yellow-browed bulbul (1/4), oriental white-eye (1/4), brown-headed Barbet (1/4), and Indian blue robin (1/1)) were positive for Haemoproteus spp. Two mosquito species were also positive for Plasmodium (3) and Haemoproteus (1) species. Phylogenetic analysis and haplotype networks created using positive sequences of haemoparasites showed that a Plasmodium clade was shared by Cx nigropunctatus mosquitoes and the migratory bird, Indian pitta. The majority (85%) of the Plasmodium and Haemoproteus sequences of this study were not linked to the well-characterized species suggesting the distinct nature of the lineages. Associations between mosquito species and blood parasites of birds suggest the possible vector status of these mosquitoes.