Epidemiology of Feline Panleukopenia Virus Infection in Domestic Cats of Barishal District, Bangladesh

Panleukopenia in cats is a highly contagious disease. The feline panleukopenia virus (FPV), belonging to the Parvoviridae family, is the causal agent of feline panleukopenia (FP) (Truyen et al., 2009). FP is also known as feline distemper in cats. FPV is a non-enveloped, single-stranded DNA virus. Cats infected with FPV exhibit a range of clinical signs, including diarrhea, depression, vomiting, and dehydration (Awad et al., 2019). It is characterized by enteritis, leukopenia, and aberrant development (Clemens and Carlson, 1989). The FPV, which is related to canine parvovirus type 2 (CPV-2) and other parvoviruses of carnivores, is the cause of feline panleukopenia, a serious disease that affects cats (Greene and Addie, 2005). A feline ataxia syndrome has been identified, which is caused by lytic viral replication impairing cerebellar development in the infected kitten’s Purkinje cells (Kilham et al., 1971).

Due to the highly contagious nature of the disease, it spreads by direct contact between sick and healthy cats. The FPV can infect animals for months or even years. It can be found in cages, food bowls, litter boxes, and other public areas. The virus can be spread by ingestion of contaminated feeds, as well as by indirect contact of fomites, and through intrauterine route (Pandey, 2022). Viruses can spread in the environment through excrement, vomit fluid, urine, and saliva (Mahendra et al., 2020). When exposed to contaminated environments, FPV can survive for weeks or even months due to its great resistance to both physical and chemical agents (Uttenthal et al., 1999). The most frequent way that FPV spreads among susceptible animals is through direct contact with infected cats or their secretions. When the disease is active, it is excreted from all bodily secretions; however, FPV is most frequently found in the colon and excrement (Greene and Addie, 2005). The infected young cats (three to five months old) show different clinical symptoms, including hemorrhagic diarrhea, anorexia, vomiting, and a decrease in white blood cells (neutropenia and lymphopenia), which may become fatal in unvaccinated cats, and kittens under 12 months show the highest morbidity and mortality rates, and based on the severity of clinical signs, mortality ranges from 25 to 100% (Richards et al., 2006; Stuetzer and Hartmann, 2014). In addition, fetal infection may cause a type of immunological tolerance that allows kittens shedding the virus long after their birth (Pedersen, 1987).

FP is most commonly found in domestic, young, immunocompromised, and multi-cat families aggressive and male cats (Kruse et al., 2010). The majority of FPV cases are reported in cats under a year old. However, cats of all ages that are unvaccinated or incorrectly/improperly vaccinated remain susceptible to FPV infection. It was also reported that the disease only struck vaccinated cats who had not gotten a booster shot after 12 weeks of age, with a median age of 4 months for the affected cats (Kruse et al., 2010). Seasonal increases in vulnerable newborn kitten populations were correlated with outbreaks of FPV in cats. The majority of FPV cases are found in households with many cats, particularly in enclosed shelter settings. However, cats living outside, such as barn, feral, and stray cats may experience it (Kruse et al., 2010).

An early diagnosis of FPV infection is critical for isolating the affected cats and shielding susceptible animals from contracting secondary infections. A conclusive diagnosis cannot be made only on the basis of signs and clinical history. The test protocol is straightforward and may be carried out by both owners and veterinarians. However, the immunochromatography assay is the most rapid field diagnostic kit (FPV Ag) used in the clinical practice (Mosallanejad et al., 2009).

A few supportive and symptomatic treatments for FPV-affected cats, such as nutritional supplements, antiemetic medications, removing dehydration, correcting electrolyte imbalances, and antibiotics to control secondary bacterial infections, have also been suggested. (Chandler et al., 2008). Vaccination is recommended to prevent the disease, and the commercially available vaccines for preventing the FPV infection include Purevax feline 4, Biofel, Nobivac feline 4, the modified live virus, or an inactivated virus vaccine. Both an inactivated and a modified live virus vaccination are available for preventing the FPV infection (Gaskell et al., 2006). It is administered in two shots at 8–9 weeks of age and 3–4 weeks later, followed by a first booster shot one year later (Truyen et al., 2009). Due to high contagious nature and fatality of FPV infection in cats, a proper understanding of the prevalence and management practices is critical for its prevention and control. However, the prevalence, treatment practices and vaccination status of cats against FP in Barishal district, Bangladesh are lacking. Therefore, in this study we investigated the prevalence, mortality rate, and case fatality of FP in domestic cats in Barishal district. In addition, we also investigated the frequency of different factors like age, breed, sex, as well as the frequently occurring clinical signs and common therapeutic practices in case of FP.

The study was conducted to observe the epidemiology and diagnosis of FPV at Upazila Livestock Office, Veterinary Hospital Barishal Sadar, and Pet Clinic, Barishal, where patients were brought from different areas of the Barishal district (Figure 1). 

The study was conducted based on collecting samples from admitted patients (cats) to the hospital from November 1, 2023, to April 10, 2024. During the study, a total of 131 samples were collected from sick cats and patients’ information were recorded. In this study, different cat breeds were recorded, including indigenous, Persian, and cross-breed cats. The pet cats were kept indoors and looked after by the owners, not going outside, whereas stray cats were wondering in the forest, bush, and roadside, as well as in the in the homestead area, for food. The body weight of the cats ranged between 0.3 kg and 3.5 kg. Some of the cats had a history of vaccination against FPV infection.

After initial registration and history-taking, each case was clinically examined. The clinico-epidemiological findings of each case were recorded in the structured recordkeeping sheet. Data includes address, date, total population, housing system, species, breed, age, sex, body weight, body condition score, vaccination, de-worming, previous disease history with treatment, duration of illness, defecation, micturition, and vomiting, along with client demographic information (age, sex, education, and job). Pulse, respiration, and rectal temperature were taken; a skin fold test, examination of the mucous membrane, and different organs of the body were performed by using the methods of palpation, percussion, and auscultation. Diagnosis and drug prescription data were also recorded in the structured recordkeeping sheet. Drug data is made up of the trade names of the drugs, main and supportive drugs, dose, route, and duration.

The diagnosis of each case was performed based on the findings of the clinical-epidemiological history, examination, and rapid FPV diagnostic test kit result. The cats that manifested frequent vomiting, anorexia, foul-smelling diarrhoea, depression, and severe weakness were initially suspected of FP. Finally, it was confirmed by using a rapid diagnostic Feline Parvovirus Ag (FPV Ag) test kit following the manufacturer’s instructions (Figure 2). This kit is a chromatographic immunoassay for the qualitative detection of the FPV Ag in feline feces. In brief, the cat’s feces or vomit sample was collected by a sterile swab. After that, the swab sample was placed into an assay buffer tube, stirred thoroughly, and allowed to sit for 2 minutes. Then the cassette from the foil pouch was opened and placed on a flat, clean surface. Later, samples were collected in a dropper from the buffer-specimen mixture,

Table 1: Results of rapid test kit for the detection of FPV infection in relation to age, sex, breed, type of cats.

and 3 drops of the specimen were added to the hole of the cassette. After 5 minutes, the result was read. If both the control and test lines were produced, it was considered positive.

All of the FPV Ag test-positive cats (n=53) were given treatment that included the below regimens:

Fluid therapy: Each individual diseased cat was checked clinically and received the estimated amount of fluid therapy according to the degree of dehydration.

• Antiemetic: Ondansetron in the form of injection (Emistat) (8 mg/4 ml vial intravenously (IV) or subcutaneously (SC) by a rate of 15 mg/kg body weight.
• Antibacterial drug: ceftriaxone in the form of injection (Trizon vet, Ceftron vet) at 25–50 mg/kg body weight; metronidazole in the form of injection at 15 mg/kg body weight; or combination (ceftriaxone + metronidazole).

The proportionate prevalence of the disease was calculated using the number of identified cases divided by the total number of cases. The proportionate mortality rate of the disease was calculated using the number of deaths divided by the total number of cases. The proportionate case fatality of the disease was calculated using the number of deaths divided by the total number of identified cases.

All the data obtained were entered into Microsoft Excel 2007 (USA). Data were cleaned, sorted, and coded in MS Excel 2007 before being exported to STATA-14 (Stata Corp., 4905 Lakeway Drive, College Station, Texas 77845, USA) for descriptive analysis.

The study was conducted to observe the epidemiology and diagnosis of FPV infection in cats at Upazila Livestock Office, Veterinary Hospital Barishal Sadar, and Pet Clinic, Barishal, where patients were brought from different areas of the Barishal district. During November 1, 2023 to April 10, 2024. Out of 131 cases, 53 cases were diagnosed as positive for FP.

In this study, the overall prevalence of FPV infection was 40.45% (Table 1). The mortality rate and case fatality rate were 23.66% and 58.49%, respectively (Table 1). A total of 131 cases were categorized into ages (Table 1). There were varied prevalence of FPV infection based on the different age groups, where highest prevalence (46.77%) was found in cats of less than 3 months, followed by cats of 3 months to 8 months (44.00%), over 8 months to 1.3 years (33.33%), and over 1.3 year (25.00%) (Table 1). There were also gender and breed variations in FPV prevalence in cats, a higher prevalence was recorded in male (42.02%) than those of female (38.70%) cats, and a higher prevalence of FPV was recorded in indigenous (43.20%) and cross-breed (40.00%) cats, compared to Persian cats (30.00%). The prevalence of FPV infection was higher in pet cats (41.07%) than that of stray cats (36.74%) (Table 1).

The mortality rate in different groups of cats was 30.64%, 24.00%, 16.66%, and 10.00% in less than 3 months, 3 months to 8 months, > 8 months to 1.3 years, and > 1.3 years, respectively (Table 1). A comparatively higher mortality rate of FPV was recorded in male (24.63%) than female (22.58%) cats, and a higher mortality rate of FPV was recorded in indigenous cats (29.62%) compared with cross-breed cats (16.66%) and Persian cats (10.00%). The mortality rate of pet cats (25.00%) was higher than that of stray cats (15.78%) (Table 1).

Case fatalities of different groups of cats were also recorded. The case fatality rate in different groups of cats was 65.51%, 54.54%, 50.00%, and 40.00% in less than 3 months, 3 months to 8 months, >8 months to 1.3 years, and > 1.3 years, respectively (Table 1). Comparatively higher case fatalities of FPV infection were recorded in male (58.62%) than female (58.33%) cats, and a higher case fatality of FPV infection was recorded in indigenous cats (68.57%) compared with cross-breed cats (41.66%) and Persian cats (33.33%). The case fatality of the pet cat (60.86%) was higher than that of the stray cat (42.85%) (Table 1).

A higher prevalence of FPV infection was recorded in unvaccinated cats (42.27%) than in vaccinated cats (12.50%). A higher mortality rate of FPV infection was recorded in unvaccinated cats (25.20%) than in vaccinated cats (00.00%) (Table 2). A higher case fatality of FPV infection was recorded in unvaccinated cats (59.61%) than in vaccinated cats (0.00%) (Table 2).

Vomiting (88.67%) and diarrhea (92.45%) were the most frequent clinical signs in FP (Table 3). Temperature varied in affected cats, where the majority of the cats (71.69%) had a subnormal temperature, followed by fever (20.75%) and normal (7.54%), respectively (Table 3). Anorexia was found in 86.79% cases (Table 3). Dehydration was categorized as normal, mild, and moderate (Table 3). The majority of the cats showed moderate dehydration (66.03%), followed by mild (28.30%) and normal hydration status (5.66%), respectively (Table 3).

Antibiotics, fluid therapy, proton pump inhibitors, antiemetics, and multivitamins were mainly prescribed for feline panleukopenia in cats. Combined antimicrobials (ceftriaxone and metronidazole) (62.26%) were highly used antimicrobials, followed by Ceftriaxone (28.30%) and only metronidazole (9.43%), respectively, and the recovery rate of combined antimicrobials (ceftriaxone and metronidazole) (48.48%) was higher than Ceftriaxone (30.00%) (Table 4). The most frequently used fluid therapy was 5% dextrose (50.94%) saline, followed by normal saline (30.18%) and Hartmann’s solutions (18.86%) to maintain fluid and electrolyte imbalance in the patients, but the recovery rate of Hartmann’s solutions (50.00%) was higher than others (Table 4). Pantoprazole (56.60%) was chosen mostly over esomeprazole (37.73%) as a proton pump inhibitor, and the recovery rate of Pantoprazole (43.33%) was higher than that of esomeprazole (40.00%) (Table 4). Antiemetics (ondansetron) and multivitamins were used in 88.67% and 77.35%, respectively, with recovery rates of 44.68% and 48.78% in FPV cases, respectively (Table 4).

Feline panleukopenia is one of the highly infectious and contagious diseases and often lethal for cats. This study examined the frequency of various FPV variables, the prevalence of FPV infection in cats, commonly

Table 2: Results of rapid test kit for detection of FPV in relation to vaccination status of cats.

Table 3: Results of rapid test kit for detection of FPV in relation to health status of cats.

Table 4: Frequency distribution of given treatment for feline panleukopenia in cats.

observed clinical symptoms, and the prescriptions given in FPV infection. FP is endemic in Bangladesh, and an epidemic outbreak of FPV infection may occur (Stuetzer and Hartmann, 2014; Sultana et al., 2016). A previous study reported an overall 22.4% prevalence of FPV infection in cats of Bangladesh (Islam et al., 2010), however in this study we observed a much higher prevalence of FPV infection in cats of Barishal district, Bangladesh (40.45%). This variation could be attributed to seasonal variations, where Islam et al. (2010) conducted their study in the spring season, and ours was performed in winter.

In our study we found that FPV infection is most prevalent (46.77%) in young cats of aged less than 3 months. Previous studies also reported a higher prevalence (over 25%) of FPV infection in young cats (Kruse et al., 2010; Sultana et al., 2016). Young age groups remain more prone to infection due to less immunity and also for unvaccinated status of the cats. On the other hand, vaccination, recovered from infection and some other environmental factors might influence older cats to acquire immunity against viruses that reduce the chance of infection (Scott and Geissinger, 1999).

We found that male cats acquired more FPV infection (42.02%) than female cats (38.70%%), which are consistent with the previous report (Kruse et al., 2010). In our study 41.07% domesticated cats and 36.84% stray or rescued cats were infected with FPV, however a previous study reported a higher FPV infection (62.1%) in domesticated cats but FPV infection in rescued cats (37.9%) was almost similar (Kruse et al., 2010). In inconsistent with the findings of the previous study (Chisty et al., 2020), we also found a higher FPV infection in indigenous cats (43.20%).

Vaccinated cats (12.50%) had a lower prevalence of FPV than non-vaccinated (42.27%) (Gore et al., 2006; Scott and Geissinger, 1999).

In this study we found majority of the cats (71.69%) had a subnormal temperature, whereas a previous study reported 38.5% had a subnormal temperature (Chisty et al., 2020). Similar to other studies, we also found anorexia, frequent vomiting, diarrhea, weakness, and different level of dehydration as the prominent clinical signs in FPV infection (Truyen et al., 2009). Similar to other previous studies (Chisty et al., 2020; Sultana et al., 2016; Islam et al., 2010; Truyen et al., 2009), the diagnosis of FPV infection in our study was also done by observing clinical signs and using the rapid FPV kit test result.

In the current study antibiotics (ceftriaxone and metronidazole), fluid therapy (5% dextrose saline and 0.9% saline), antiemetic (ondansetron), proton pump inhibitor (pantoprazole, esomeprazole), antibiotics (metronidazole and ceftriaxone) and multivitamins were used as the supportive treatment. Treatment with ceftriaxone and metronidazole (48.48%) was higher than ceftriaxone (30.00%) which was very similar to previous report (Truyen et al., 2009) with few exceptions. Besides, whole blood transfusion and antiviral therapy were suggested in hypo-proteinaemic cats. Additionally, proton pump inhibitor was used in this study to reduce gastritis (Daure et al., 2017).

The study was conducted to know the epidemiology of FPV infection in cats at Upazila Livestock Office and Veterinary Hospital Barishal Sadar and at Pet clinic, Barishal. FPV infection was most commonly found in young non-vaccinated local male domestic cats. Timely vaccination is critical for preventing FPV infection in cats. As supportive treatment of FPV infection in cats, fluid therapy (5% dextrose saline and 0.9% saline), antiemetic (ondansetron), proton pump inhibitor (pantoprazole or esomeprazole), antibiotics (metronidazole and ceftriaxone or only ceftriaxone) and multivitamins preparation can be suggested.

The author is grateful to Dr. Pradip Kumar Biswas, Upazila Livestock Officer, Upazila Livestock Office and Veterinary Hospital Barishal Sadar and Hospital attendants of Upazila Veterinary Hospital, Babuganj for their cooperation.

MIH and SRAB collected and analyzed the data. SRAB collected the sample and tested it with test kits. MIH designed the research and wrote the manuscript. MEHK edited the manuscript and supervised activities. All authors read and approved the final version of the manuscript.

The authors have declared no Conflict of Interest.