Prevalence of Leucocytozoon infection in domestic birds in Ghana

Abstract

Leucocytozoon is a haemosporidian parasite known to cause leucocytozoonosis in domestic and wild birds in most parts of the world. It is an important pathogen, as some species can be pathogenic, especially in domestic birds. One of the factors affecting poultry health management worldwide is parasitism. However, the study of haemosporidian parasites in Ghana is still lacking. This study sought to assess the prevalence and diversity of Leucocytozoon parasites in domestic birds in Ghana. Blood samples were collected from domestic birds in Ghana's Bono and Eastern regions to screen for Leucocytozoon parasites. Thin blood smears were prepared for microscopy and DNA was extracted from whole blood kept in ethylenediaminetetraacetic acid (EDTA) tubes for PCR. Due to the large number of samples, real-time PCR was performed to amplify the conserved rDNA gene. Two different nested PCR protocols were performed on the positive samples obtained from real-time PCR results, to amplify a partial region of the mitochondrial cytochrome b gene and the amplicons were sequenced. Sequencing revealed six new lineages of Leucocytozoon sp. recovered in 976 individual domestic birds and these sequences were deposited in the National Center for Biotechnology Information (NCBI) GenBank. An overall Leucocytozoon prevalence of 11.6% was reported in all birds sampled. The most prevalent lineage LGHA146 (GenBank accession no. OM643346) (93.8%) was found infecting 3 bird species, Gallus gallus, Meleagris gallopavo, and Anas platyrhynchos. Phylogenetic analysis revealed that the new lineages (GenBank accession nos. OM643342, OM643343, OM643344, OM643345, OM643346, and OM643347), reported in this study were closely related to Leucocytozoon schoutedeni. We suggest that further studies be conducted to evaluate the effect of these parasite species on the general well-being of poultry in Ghana.

Fig 1. Prevalence of Leucocytozoon sp. lineages in different bird species.

Accession numbers of lineages are shown on the x-axis and lineage prevalence is on the Y-axis.

Fig 2. A maximum-likelihood phylogenetic tree constructed with partial mitochondrial cytochrome b gene sequences.

Six Leucocytozoon lineages (shown in the yellow box) found in this study were used together with others obtained from the NCBI GenBank and Malavi databases. Lineage names in the pink box and black text without the box represent related Leucocytozoon sequences from South Asia. Lineage names in blue text represent L. schoutedeni found in Uganda. Values on nodes denote bootstrap analysis based on 1000 replicates. Plasmodium relictum GRW04 (AF254975/AY172850) was used to root the tree.