A door-to-door prevalence study of feline immunodeficiency virus in an Australian suburb

Abstract

A door-to-door survey was conducted within the limits of the suburb of Douglas in northern Queensland, Australia, to determine the prevalence of feline immunodeficiency virus (FIV) infection in the overall population of domestic cats. Previous FIV prevalence studies have relied on convenience sampling strategies, leaving out an important group of pet cats that do not receive regular veterinary attention. Saliva was selected for testing because collection was non-invasive and was likely to achieve a high rate of participation. Ninety-six cats were surveyed and tested for salivary antibodies against FIV and with real-time polymerase chain reaction (PCR). PCR was considered to be the gold standard and a cat was considered to be FIV-positive if sequencing results on a PCR product of appropriate size matched previously published FIV genome sequences available in GenBank. Results showed 10/96 cats to be infected with FIV subtype A, indicating a prevalence of 10.4% (95% confidence interval: 4.4–16.4) in the area studied. High risk associations were established with the roaming lifestyle of the cat (P <0.002), presence of abscesses (P <0.03) and occurrence of bite wounds (P <0.10). This is the first known cross-sectional study of a population of urban northern Australian cats living in an affluent suburb and presenting saliva as a potential non-invasive sample for large-scale epidemiological surveys on FIV.

Introduction

Feline immunodeficiency virus (FIV) is a lentivirus of the Retroviridae family that infects domestic cats worldwide.¹ This virus has a particular tropism for immune system cells and can produce a progressive immunosuppression in which opportunistic infections and cancer are commonly described, and often leads to the death of the infected cat.^2,3 Free-roaming male cats are at high risk of infection^3,4 as they become infected mainly through bite wounds when they engage in territorial fights with FIV-infected cats.^3,5 FIV has been isolated from blood, saliva, semen and cerebrospinal fluid of naturally- and experimentally-infected cats.³

In Australia, FIV studies have relied on convenience sampling strategies by acquiring blood samples from apparently healthy cats visiting veterinary clinics. ‘Clinically sick’ cats were also considered, and blood samples for this group were included after pathology laboratories confirmed a clinical abnormality. Four different studies estimated the seroprevalence of FIV to be approximately 6.5%⁶ and 8%⁷ in ‘clinically healthy’ cats, and 10%,⁸ 26%⁹ and up to 51%⁷ in those considered to be ‘clinically sick’. However, an unknown proportion of owners do not present their cats to veterinarians and, consequently, this important group of cats has been excluded from previous Australian prevalence reports.

The purpose of this study was to determine the prevalence of FIV infection by sampling cats door-to-door in a suburb of northern Australia and comparing our results with those obtained by convenience sampling studies. We also aimed to study the demographics of the cat population in such a suburb.

Materials and methods

Study design

This study was approved by the Human Ethics Committee and the Animal Ethics Committee of James Cook University (reference numbers: H3580 and A1476 respectively).

A door-to-door random sampling approach based on the study design of Allan et al¹⁰ was conducted between February 2010 and June 2010 in the suburb of Douglas, city of Townsville, northern Queensland, Australia. With a population of 5993,¹¹ Douglas is mainly a residential suburb that also contains James Cook University and the Townsville Hospital, and is located west of the city centre. A detailed spatial map obtained online from Google Earth/Maps in December 2009, showing every lot in the suburb, was used to assign a number to each house, comprising a total of 2193 residential properties contained in 122 streets. Households to be surveyed were randomly selected using the function ‘RANDBETWEEN’ in Microsoft Excel 2007. Each random number obtained was matched with the corresponding house on the map indicating the address of the property to be surveyed.

The sample size was determined using the method described by Thrusfield¹² with a 95% confidence level and 5% margin of error, an average referential prevalence of FIV in Australia of 15%^6–9 and a total of 2193 residential properties. Because the registration of pet cats was not mandatory prior to this study, and therefore no record of the size of the population of pet cats existed, the decision to obtain information on 200 cat-owning households was made.

Households were surveyed door-to-door requesting participation if they owned a pet cat. However, if there was no reply to a door knock an information sheet requesting participation was left in the mailbox, which included the contact details of the interviewer. Households with ‘no replies’ were revisited on two further occasions. Owners of surveyed households agreeing to participate in this study were asked to fill out a single-page questionnaire, divided into five sections comprising short-closed and multiple-choice questions, with information regarding cat ownership, cat demographics, roaming lifestyle, vaccination status and FIV-related observations, such as frequency of bite wounds and abscesses. Only pet cats aged 6 months or older were included in this study to minimise false-positive results caused by the effects of maternally transferred anti-FIV antibodies.

Sample collection and preparation

Saliva was selected as the sample of choice because collection was non-invasive, easily carried out at the doorstep of the household to be surveyed and was thought likely to achieve a high rate of participation. Two saliva samples were obtained from each participating cat by rubbing sterile swabs, individually packed in sealed transport tubes (Sarstedt), against the inner cheek mucosa for approximately 30 s. One swab was obtained from each side of the mouth and stored at −80°C prior to testing.

Saliva samples were prepared by transferring the swabs to a 1.7 ml microcentrifuge tube (LabAdvantage) and breaking the plastic rod, leaving only the cotton end, prior to adding 100 µl of phosphate buffered saline solution. The samples were centrifuged at 10,000 × g for 20 s at room temperature to help disrupt the cotton swab.

For preliminary studies and control purposes, whole blood and saliva swabs were obtained from three known FIV-positive and two FIV-negative cats. FIV-positive cats had been previously diagnosed by commercial laboratories; both FIV-negative cats had been kept consistently indoors since birth, had no contact with other cats with outdoor access and were later confirmed to be free of FIV using polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Peripheral blood mononuclear cells from control cats were isolated using Ficoll-Paque Plus (Amersham Bioscience) density gradient centrifugation from whole blood collected in 4.0 ml ethylenediamine tetra-acetic acid tubes (BD Vacutainer System) and were stored at −80°C until testing. Saliva swabs from control cats were prepared in the same manner.

Detection of salivary antibodies

One saliva swab from each participating cat was used to detect the presence or absence of salivary antibodies against FIV using the Snap Feline Triple test commercial kit (Idexx Laboratories). This is an ELISA for the detection of FIV antibody, feline leukaemia virus antigen and heartworm (Dirofilaria immitis) antigen in serum, plasma or anti-coagulated whole blood. The manufacturer’s protocol was followed using the product obtained from the preparation of each saliva swab as a substitute for the recommended blood-derived sample. Preliminary trials with control samples were executed prior to testing of the field samples to ensure matching results between blood and saliva.

PCR amplification, sequencing and FIV subtyping

The second saliva swab from each participating cat was used to detect FIV nucleic acid with real-time PCR by targeting the gag and env genomic regions with primer sequences from previously published studies on FIV.^13–15 Amplification was performed using a RotorGene 6000 (Corbett Research) thermal cycler machine in 20 µl with 1 × (10 µl) Go Taq Hot Start Colourless MasterMix (Promega), 0.6 µM mixed primers, 5 µM SYTO 9 (Invitrogen), 10 ng DNA template and nuclease-free water to complete 20 µl. In PCRs carried out with the primer set FIV0771f and FIV1081r, a TaqMan probe was used at 0.1 µM instead of the SYTO 9 fluorescent dye.

The primer set FIV1026f (5’-GGC ATA TCC TAT TCA AAC AG- 3’) and FIV1700r (5’-AAG AGT TGC ATT TTA TAT CC-3’) was used with an initial denaturation for 2 mins at 95°C, followed by 60 cycles each at 95°C for 10 s, 50°C for 40 s and 72°C for 60 s. Cycling conditions for primer set FIV0771f (5’-AGA ACC TGG TGA TAT ACC AGA GAC-3’) and 1081r (5’-TTG GGT CAA GTG CTA CAT ATT G-3’) with TaqMan probe FIV1010p (5’-FAM-TAT GCC TGT GGA GGG CCT TCC T-BHQ-1-3’) consisted of an initial denaturation at 95°C for 3 mins followed by 60 cycles of 15 s at 95°C, 60 s at 60°C and 60 s at 72°C. PCR assays targeting the env gene used primers SU3f (5’-ATW CCA AAA TGT GGA TGG TGG-3’) and SU4r (5’-AAT AAG GTC ATC TAC CTT CAT-3’) with an initial denaturation at 94°C for 60 s, followed by 40 cycles of 95°C for 60 s, 55°C for 60 s and 72°C for 60 s, and a final extension at 72°C for 7 mins.

All cycles were performed with one positive control reaction (FIV-infected cat sample), one negative control reaction (FIV-free cat sample) and a no template control (NTC). Two percent agarose gel electrophoresis was used to confirm PCR products of 674 base pairs for primer set FIV1026f and FIV17000r and 310 base pairs for FIV0771f and FIV1081r. PCR products were sequenced by Macrogen. The Basic Local Alignment Search Tool (http://blast.ncbi.nlm.nih.gov/blast.cgi) was used to determine similarity with previously published sequences. For this study, a cat was considered to be FIV infected when nucleotide sequences recovered produced a matching result with those available in the GenBank database.

Data analysis

Data obtained from the questionnaires were captured in Microsoft Excel 2007 and analysed using the statistical software package SPSS version 17.0 (IBM).

The prevalence of FIV was determined by dividing the number of FIV-infected cats detected by the total number of cats surveyed with a 95% confidence interval (CI). Differences between groups were assessed by the Pearson χ² test, and statistical significance was set at P <0.05. A logistical regression model was also developed to examine risk factors captured in the questionnaire associated with FIV presence in a household.

Kappa values were calculated to measure the agreement between tests, the salivary antibody test and real-time PCR of the saliva of each cat. As suggested by Landis and Koch,¹⁶ a kappa value of 0.0–0.40 was considered as poor-to-fair agreement, a kappa value of 0.41–0.60 was considered as moderate agreement, a kappa value of 0.61–0.80 was considered as substantial agreement and a kappa value of 0.81–1.00 as considered as excellent agreement.

Results

Pet cat demographics

A total of 511 households was surveyed, of which 93 were identified as cat-owning dwellings. Fourteen houses (2.7%) contained a single cat, but refused to participate in the study; five (1%) agreed to participate, but the cat was absent after multiple visits. Consequently, 74 households were used in this survey. No pet cats were kept in 304 (59.5%) of the surveyed households and 114 (22.3%) were recorded as ‘no reply’ after the third visit. The study showed that 23.4% [93/397 (95% CI: 19.6–27.2)] of households owned a cat in the area under study.

The 74 participating households kept 96 cats. The mean age of these cats was 5.6 years (median 5.0, range 0.5–21 years). Among these dwellings, 56/74 [75.7% [95% CI: 66.1–85.3)] were single cat households, while 18/74 [24.3% (95% CI: 14.7–33.9]) housed multiple cats; 15/74 [20.3% (95% CI: 11.3–29.3]) kept two cats; 2/74 [2.7% (95% CI: 0–6.3)] kept three; and 1/74 [1.3% (95% CI: 0–4]) kept four. The ratio of male to female cats was 49:47, and 90/96 [93.7% (95% CI: 89–98.5]) were de-sexed cats. Crossbred cats [65/96; 67.5% (95% CI: 58.3–76.7)] were more commonly found than purebreds [31/96; 32.5% (95% CI: 23.3–41.7]). Cats were mostly either adopted stray cats [19/96; 19.8% (95% CI: 12–27.6]), or obtained from an acquaintance [17/96; 17.7% (95% CI: 10.2–25.2)], a breeder [13/96; 13.5% (95% CI: 6.8–20.2]), the Royal Society for the Prevention of Cruelty to Animals [12/96; 12.5% (95% CI: 6–19)], a pet store [10/96; 10.4% (95% CI: 4.5–16.5)], a veterinary clinic [6/96; 6.3% (95% CI: 1.6–11.1)] or a pound [3/96; 3.1% (95% CI: 0–6.5)]. The owners of the remaining cats [16/96; 16.7% (95% CI: 9.4–24)] did not remember where the cats were obtained from and were therefore classified with as of unknown origin. Regarding the roaming lifestyle of the sampled cats, the majority [65/96; 67.7% (95% CI: 58.6–76.9)] spent some time both indoors and outdoors, while 26/96 [27.1% (95% CI: 18.3–35.7]) were always kept indoors and 5/96 [5.2% (95% CI: 0.9–9.5)] were always kept outdoors. Demographical information is presented in Figure 1, and information regarding core and FIV vaccination status of the cats is presented in Table 1.

Figure 1

The distribution of surveyed cats in regard to reproductive status, breed, origin and roaming lifestyle. RSPCA = Royal Society for the Prevention of Cruelty to Animals

Table 1

Vaccination status [core and feline immunodeficiency virus (FIV)] of the pet cats surveyed. Core vaccines include those that protect against feline panleukopenia virus, feline calicivirus and feline herpesvirus-1²⁶

Core vaccines			FIV vaccine
Number of cats	(%)		Number of cats	(%)
9	9.3	Not sure if ever vaccinated	46	47.9
6	6.3	Never vaccinated	30	31.3
81	84.4	At least once	20	20.8
For cats known to have been vaccinated, interval since last vaccination*
43	44.8	<1 year	9	9.4
17	17.7	1–3 years	5	5.2
21	21.9	Unknown timing	6	6.2

Interval from the sampling date

Analysis of questionnaire responses demonstrated strong significant associations between the roaming lifestyle and the presence of both bite wounds and abscesses (P <0.01) using univariate analysis. Table 2 presents the collected data on the frequency of bite wounds and abscesses of the surveyed cats.

Table 2

Distribution of bite wounds and abscesses of the pet cats surveyed

		Bite wounds	Abscesses
Never	Number of cats	38	62
	(%)	39.6	64.6
	95% CI	30.3–46.5	55.2–74.0
Rarely	Number of cats	30	22
	(%)	31.3	22.9
	95% CI	22.2–40.4	14.7–31.3
Often	Number of cats	10	5
	(%)	10.4	5.2
	95% CI	4.4–16.4	0.9–9.5
Unknown	Number of cats	18	7
	(%)	18.7	7.3
	95% CI	11.1–26.3	2.2–12.4

95% CI = 95% confidence interval

Preliminary studies

In every serological test, the control spot of the Snap device became evident after test activation. All samples originating from previously diagnosed FIV-infected cats produced a positive result, with visibly colored FIV-reactive spots. Tested saliva produced the same intensity of colouration as did blood in the FIV-reactive spots when blood and saliva from the same cat were tested at the same time.

For the molecular testing, all samples obtained from previously diagnosed FIV-infected cats resulted in a positive amplification result and observation of the anticipated band size in both blood and saliva. Additionally, all samples obtained from the FIV-free cats and the NTC produced no amplification products.

Cat saliva swab testing

A total of 96 cats was tested for FIV salivary antibodies using the Snap Feline Triple test and with real-time PCR of saliva swabs. Real-time PCR assays produced consistent positive results for 10/96 cats [10.4% (95% CI: 4.4–16.4)], and these cats were confirmed to be infected with FIV when PCR product sequences were compared with available sequences in the GenBank database and produced a 94–98% homology to FIV genotype A sequences. Seven of the FIV infected cats were also positive for salivary antibodies and none was FIV-vaccinated (Figure 2).

Figure 2

Comparison of the positive saliva samples obtained for each diagnostic test. Sample S4 had an unknown feline immunodeficiency virus (FIV) vaccination status, but was positive for salivary antibodies and negative on polymerase chain reaction (PCR)

However, two of the cats positive for salivary antibodies, but negative by real-time PCR, were FIV-vaccinated and were therefore considered to have yielded false-positive results. Also, seven known FIV-vaccinated cats were not positive for salivary antibodies. One additional sample (S4) was positive for salivary antibodies, but negative in the PCR assays, and this cat had an unknown FIV vaccination status. Multiple failed attempts to contact the owner of this cat to confirm its FIV vaccination status were made as the owner was no longer interested in further participation. In total, eight samples were considered to be positive for salivary antibodies generated by natural exposure to FIV.

There were no cases of FIV-vaccinated cats with a positive result for both salivary antibody detection and FIV DNA detection by PCR.

The corresponding Kappa value between both diagnostic tests was 0.76 (95% CI: 0.64–0.87).

FIV epidemiological findings

The prevalence of FIV in the area studied was 10.4% (95% CI: 4.4–16.4). The mean age of FIV-infected cats was 6.7 years (median 6.5, range 1–14 years) and the proportion of males to females was 7:3. Only one male, FIV-infected cat was sexually entire. The strongest associations in this study linked FIV infection to the roaming lifestyle of the cat (P <0.002) and to the presence of abscesses (P <0.03). A lower association (P <0.10) was found with the occurrence of bite wounds (Table 3). A logistic regression model failed to show an association with any of the risk factors.

Table 3

Risk factors distribution and χ² test analysis of pet cats surveyed in this study. For significant associations, P-values are presented. This table does not include missing data

	Risk factors	Number of cats	FIV-infected		Free of FIV
			(%)	Number	(%)	Number
Sex	Male	49	70.0	7	49.4	42
	Female	46	30.0	3	50.6	43
	Total	95		10		85
De-sexed	Yes	87	90.0	9	91.8	78
	No	8	10.0	1	8.2	7
	Total	95		10		85
Roaming lifestyle*	Always indoors	26	0	0	30.2	26
	Both indoors and outdoors	65	80.0	8	66.3	57
	Always outdoors	5	20.0	2	3.5	3
	Total	96		10		86
FIV vaccination	Yes	20	0	0	42.6	20
	No	30	100.0	3	57.4	27
	Total	50		3		47
Observed abscesses†	Never	62	50.0	5	72.2	57
	Rarely	22	20.0	2	25.3	20
	Often	5	30.0	3	2.5	2
	Total	89		10		79
Observed bite wounds‡	Never	38	40.0	4	50.0	34
	Rarely	30	20.0	2	41.2	28
	Often	10	40.0	4	8.8	6
	Total	78		10		68

FIV = feline immunodeficiency virus

Significant association considering P <0.002

†

Significant association considering P <0.03

‡

Significant association considering P <0.10

Discussion

Study design

Despite the considerable efforts to maximise the number of cat-owning households recruited for this survey, the number of pet cats encountered was lower than anticipated. Pet cat registration was not mandatory prior to this study and therefore the population of pet cats was unknown. Surveying was carried out from 3 pm until 7 pm on weekdays and all day on weekends to increase the chances of finding cat owners at home. However, 76.6% of the households surveyed did not own a cat. Other Australian surveys^17,18 aiming to obtain demographic information on pets approached owners by telephone or mail, but these methods were not suitable for this study, which aimed to obtain fresh saliva samples from pet cats to be tested for FIV. The response rate achieved in this survey (85%) was higher than previous studies using mailed questionnaires (38.6%),¹⁸ but, unfortunately, the low rate of cat ownership was a limiting factor. This type of surveying also reduced missing information in the questionnaires because these were filled out with the help of the surveyor.

Pet cat demographics

We were able to produce data on age, gender, breed, reproductive status and husbandry (roaming lifestyle and vaccinations) of pet cats living in a city in northern Queensland, Australia. Two previous studies have reported information on pet cats in Australia — one in Sydney¹⁸ and one in Perth¹⁷ — but this is the first known study carried out in Queensland and northern Australia.

In 2003, Baldock et al¹⁹ reported a decrease in the population of pet cats in Australia from 1979 to 1999, and predicted a continuous decline in pet cat ownership using a simple life table model. A different study estimated the city of Perth to have 28.6% of households owning a cat in 1990,¹⁷ while a survey in 2009 discovered that 22.5% of households in Sydney owned a cat.¹⁸ Our results revealed 23.4% (95% CI: 19.6–27.2) of cat-owning households in the area studied, in which the upper confidence interval exceeds the rate obtained in recent reports for Sydney and therefore differs from the estimates of Baldock et al.¹⁹ However, it would be incorrect to make further assumptions on the predicted decline of cat ownership in Australia based on the results obtained from individual cities. The Australian Companion Animal Council report also differed from the estimates of Baldock et al¹⁹ when they described a slight increase — to 23% — of cat ownership in Australia in 2009, which is similar to the rate observed in this study, but which continues to be significantly lower than in the USA (33%), although it is higher than in the UK (20%).²⁰

This study revealed that the majority of cats (67.7%) spent some time both indoors and outdoors, while only 5.2% of cats were considered to be exclusively outdoor cats. In contrast, the proportion of pet cats kept exclusively indoors was nearly fivefold higher (27.1%). The consequences of owning a free-roaming cat (cat fights, exposure to infectious agents such as FIV, car accidents, and, particularly in Australia, the risk of snake bites and other envenomations) may explain why many owners elect to keep their cats 100% indoors.

Salivary antibodies and PCR assays for FIV diagnosis

Studies on the detection of salivary antibodies and the use of PCR on saliva of FIV-infected cats have been reported in two previous articles.^21,22

Serological false-positive results can occur due to the transference of maternal antibodies from FIV-infected mothers to kittens of up to 6 months old,²³ but, more importantly, in FIV-vaccinated cats of any age.²⁴ The only commercially available FIV vaccine is an inactivated whole-virus vaccine, which induces the production of antibodies indistinguishable, by routine methods, from those occurring after natural infection.^4,24,25 Whether or not cats are vaccinated should be decided by owners after carefully considering the implications of a false-positive serological result, particularly in those cats that spend most of their time outdoors and are at greater chance of getting lost. Antibody detection with commercial in-house ELISAs like the one used in this study continues to be the most common diagnostic tool for FIV detection in veterinary clinics, but particularly in shelters and pounds. Shelters and pounds are known to use serological quick in-house tests (like the one used in this study) and cats with a positive result are often euthanased. As a result, microchipping FIV-vaccinated cats is often recommended to ensure pet cats are returned to their owners and to avoid fatal consequences. Nevertheless, the results of this study identified numerous owners not aware of the FIV-vaccination status of their pet cat.

The preliminary studies performed with the control samples (three FIV-infected and two FIV-free cats) produced matching results between blood and saliva samples in the same cat. However, a weakness of this study was that not enough known FIV-infected cats could be obtained for control purposes. To counteract this, we used three separate PCR assays targeting different areas of the FIV genome and decided to make PCR our gold standard. Molecular findings showed repeatable positive results with the three different PCR assays when they were compared with sequences previously published in the GenBank database.

The sensitivity and specificity of the Snap Feline Triple test was lower when used with saliva, but this was expected given that this test was optimised to be used with anti-coagulated whole blood, serum and plasma. Nonetheless, this test was able to recognise the majority (7/10, 70%) of FIV-infected cats encountered. However, further studies would be needed to optimise and validate a FIV test to detect antibodies in the saliva of cats.

Unfortunately, compiling information about pet cats in a study of this design relies on the memory of the owners to recall events such as the last date of FIV vaccination and the prior presence of abscesses and bite wounds. We were able to experience first hand the consequences of an incorrectly identified cat when sample S4 produced a positive result for salivary antibodies. This was not considered to be a true FIV-infected cat as none of the three PCR assays produced a positive result; however, the vaccination status of this cat remains unknown and so does the cause of this false-positive result.

A kappa value of 0.76 (95% CI: 0.64–0.87) suggested a substantial agreement between the salivary antibody test and real-time PCR.

Prevalence of FIV infection

Previous studies of the prevalence of FIV in Australian cats may have been biased by considering only those animals receiving veterinary care. The 10.4% (95% CI: 4.4–16.4) prevalence of FIV discovered in this study, in which all cats were observed as ‘apparently healthy’, is higher than any previously reported within the ‘clinically healthy’ groups (6.5% and 8%)^6,7 and very similar to one of the percentages obtained for the ‘clinically sick’ groups in previous studies (10% and 26%).^8,9 However, because we used a different method from the one used in previous studies that looked at samples from veterinary clinics and pathology laboratories, it is not possible to say whether there is, in fact, a higher prevalence of FIV in the area studied owing to the inclusion of those cats that do not receive veterinary attention. Previous authors did not include confidence intervals for the prevalences of FIV discovered in their studies so proper comparisons cannot be made. Conversly, the observed difference in the prevalence of FIV obtained might only be because of a different location of study.

The risk factors obtained in this study are consistent with prior studies that continue to relate free-roaming cats with a higher rate of FIV infection^5–7,24 and with observations that are consistent with the mode of transmission of the virus.^3,5 A suitable logistic regression model could not be designed owing to the small data sets obtained for each significant variable, but confounding variables could be considered by exploring the nature of the significant risk factor as only cats with outdoor access could be bitten by other outdoor cats.

Conclusions

This is the first known study of FIV in a population of urban Northern Australian cats. We recognise that a larger number of surveyed pet cats would have made this study stronger, but we hope this will motivate researchers to carry out more extensive studies and examine the capacity of this non-invasive sampling approach to be used in large-scale epidemiological surveys. Saliva is also a less expensive sample to obtain than blood, requiring only a sterile cotton swab to rub against the inner cheek mucosa of those cats to be tested. Sampling is also less technically demanding. The work described in this article presents a preliminary study on how saliva could be used to carry out a large-scale epidemiological survey on FIV with a new approach that does not require the standard methods of contacting veterinarians and leaving out an important group of cats that are more likely to be FIV-infected.

Footnotes

Acknowledgements

We are very grateful to Domenic Dell’Osa (Idexx Laboratories, Australia) and Idexx Laboratories for supporting this study and providing the Snap Feline Triple tests.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Conflict of interest

The authors do not have any potential conflicts of interest to declare.

Accepted: 2 May 2013

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