Epidemiology and molecular characterization of Feline panleukopenia virus from suspected domestic cats in selected Bangladesh regions

Abstract

Feline panleukopenia (FPL) is a highly contagious cat disease and is endemic in Bangladesh. The study aims to describe the epidemiology and molecular characterization of the Feline panleukopenia virus from the suspected domestic cats in selected Bangladesh regions. Randomly, 161 rectal swabs were collected from the pet hospitals between July 2021 and December 2022. A structured questionnaire was administered through face-to-face interviews with cat owners in order to collect data on potential risk factors for FPL, such as age, sex, sharing litter boxes and every day utensils in multicat households, vaccination history, hospital visits for other diseases, and season. The rectal swabs were tested by PCR targeting the VP2 capsid protein gene, and six PCR-positive samples were further sequenced for molecular characterizations. The risk factors for FPLV were identified using multivariable logistic regression analysis. The overall prevalence of FPL among suspects was 22.9%. The mortality and case fatality were 10.6%, and 45.9%, respectively. However, mortality in kittens was significantly higher (16.4%) than younger cats. The odds of FPL were 8.83 times (95% CI: 3.14-24.85) higher among unvaccinated cats than vaccinated cats. The winter season had almost six times (95% CI: 1.38-24.40) higher odds of FPL than rainy season. In a multicat house, the odds of FPL was about five times (95% CI: 1.93-13.45) higher for cats that shared a litter box and food utensils compared to those that did not engage in such sharing. Visiting hospitals for other reasons nearly triples the odds of FPL (OR: 2.80, 95% CI: 1.04-7.54) compared to cats that do not visit hospitals. Analysis of partial sequence of the VP2 gene revealed genetic variations among the isolates from different regions. Among these isolates, four were identical to FPLV isolates from South Korea and China, while one showed complete homology with FPLV isolates from Thailand. In contrast, the remaining one was 100% identical to Carnivore protoparvovirus-1 isolated from a feline sample in Italy. Our isolates were classified into three distinct clades alongside Feline panleukopenia virus and Carnivore protoparvovirus-1. One in every three suspected cats was infected with Feline panleukopenia. Regular vaccination of the cats, especially those that share common litter box and food utensils and visit hospitals for other purposes, will help reduce the prevalence of FPL in Bangladesh. Besides, it is worth emphasizing the existence of genetic diversity among the circulating Feline panleukopenia viruses in Bangladesh.

Fig 1. Bangladesh map showing different sampling areas of Feline panleukopenia virus.

Note: This map is created by our team using ArcGIS version 10.1(http://www.esri.com/arcgis).

Fig 2. Identification of Feline panleukopenia virus by polymerase chain reaction.

Gel electrophoresis showing VP2 capsid protein genes amplicons of Feline Panleukopenia virus (695bp). In Lanes: M- 100 bp DNA ladder (Promega, USA) P: Positive control N: Negative control, Lane S1-S10: Complies with the Samples of FPLV showing approximately 695 bp.

Fig 3. Phylogenetic tree of FPLV.

The Neighbor-Joining tree was constructed using 33 partial VP2 gene sequences of Carnivore protoparvovirus-1, Feline panleukopenia virus, Canine parvovirus, Mink enteritis virus, and Raccoon parvovirus. The evolutionary distances between sequences were calculated using the Tamura-Nei method. The evolutionary analyses were conducted using MEGA11 software [31] and the tree was visualized in iTOL. In the tree, the sequences obtained in this study are highlighted in red.