1

Prevalence of vector borne diseases in a population of Sri Lankan

dogs

Abstract

Background: This study investigated the occurrence of canine TBDs in a set population of dogs in the

region of Colombo, Sri Lanka using a combination of Snap tests and blood smear examination. There are no

published reports on the presence of canine TBDs, Dirofilaria, Borrelia, Anaplasma, Ehrlichia, Hepatazoon,

and Babesia in Sri Lanka.

Methods: Samples of blood were collected into EDTA from a peripheral vein of 80 dogs in Colombo, Sri

Lanka. Snap tests were used to test for D.immitis, B. burgdorferi, E. canis/E. ewingii, A. phagocytophilum/A.

platys. Blood smears were also prepared from each sample, fixed and stained with a Wright-Gimesa stain

and analysed by microscopy.

Results: On microscopic evaluation of blood smears Hepatazoon gamonts were observed in 7 dogs (8.75%),

while Dirofilaria species were found in 4 dogs (5%). Snap tests indicate a total of 34 dogs (42.5%) were

positive. Ehrlichia was the most common with 29 dogs (36.25%) positive, followed by Anaplasma with 22

dogs (27.5%) positive, co-infection with both of these was also high with 19 dogs (23.7%) positive for both.

Potential tick vectors were found on 32 dogs (40%).

Conclusions: At least 4 canine TBDs were found to exist in the dog population in Sri Lanka. Ehrlichia was

found to be the most common pathogen. Co-infection of canine TBDs is also observed in Sri Lankan dogs.

2

Abbreviations

EDTA - Ethylenediaminetetraacetic acidCanine TBDs – Canine TBDs A. platys – Anaplasma platys

A. phagocytophilum - Anaplasma phagocytophilum

R. sanguineus - Rhipicephalus sanguineus

E. canis – Ehrlichia canis

E. chaffeensis – Ehrlichia chaffeensis

E. ewingii – Ehrlichia ewingii

E. ruminantium – Ehrlichia ruminantium

D. immitis - Dirofilaria immitis

D. repens - Dirofilaria repens

B. ceylonensis - Brugia ceylonensis

B. malayi- Brugia malayi

B. canis - Babesia canis

B. gibsoni - Babesia gibsoni

H. canis - Hepatazoon canis

H. americium - Hepatazoon americium

B. burgdorferi - Borrelia burgdorferi.

BPT – Blue Paw Trust

PCR – Polymerase chain reaction

HME - human monocytic ehrlichiosis

3

1.0 Introduction

Vector-borne diseases account for 17% of the estimated global burden of infectious diseases in dogs [1].

There are many studies on vector-borne parasites infecting dogs around the world, [2,3,4,5] however, there

has been little data collected on the prevalence of these parasites on dog populations in Sri Lanka.

The dog population within Colombo, Sri Lanka is about 20,000. Within Sri Lanka approximately 3 million

dogs are free-roaming, however these numbers are changing due to sterilization clinics and rabies

vaccination projects.

Due to this high number of roaming dogs there is a persistent interaction between vaccinated and non-

vaccinated dogs, aiding disease transmission throughout the population. Totton et al, 2011 observed that

stray dogs are more likely to carry disease, exhibit poor body condition and malnourishment and be subject

to increased stress. These factors may cause them to be immunosuppressed and therefore more likely to

contract these communicable diseases [6].

1.1 Ticks:

Ticks are important vectors of disease in dogs and humans, as many of the diseases they carry are zoonotic

[2]. Ticks are well adapted to transmit a variety of organisms including viruses, bacteria and protozoa [7].

The prevalence of ticks in Sri Lanka is due to several factors such as availability of host species and humid

climate [8]

Ticks are obligate blood-feeding ecto-parasites (figure 1) that attach to hosts for a substantial amount of

time, allowing sufficient opportunity for disease transmission [8,9]. A total of 22 different tick species were

found in Sri Lanka [8], 21 of these were from wild animals. Rhipicephalus sanguineus was the most

common species in wild animals, this is significant as R. sanguineus is a carrier of 4 canine TBDs [10,11].

Ehrlichiosis, Anaplasmosis, Borreliosis, Dirofilariosis, Babesiosis and Hepatazoon are canine TBDs

considered endemic in warm climate zones [12]. The prevalence of these diseases were examined.

4

One of the predominant reasons for analysing these diseases was due to the zoonotic potential of all but

Hepatazoon. Our aim was to investigate the prevalence of these diseases in order to assess the zoonotic risk.

1.2 Ehrlichia

A gram-negative, obligate, intracellular bacterium from the family Anaplasmataceae [13,14,15,16]. There are

4 different Ehrlichia species; E. canis (worldwide) and E. chaffeensis (USA) E. ewingii (USA) and E.

ruminantium (Africa) [11]. E. canis is the most common species followed by E. ewingii. It is spread by tick

vectors, primarily Rhipicephalus sanguineus (brown dog tick) which is very common in Sri Lanka [8] also

Dermacentor variabilis transmits E.canis and Amblyomma americanum transmits E. ewingii [11]. The

bacterium predominately affects monocytes, macrophages and lymphocytes, with neutrophils and

eosinophils occasionally affected. In dogs there are several clinical signs associated with infection such as

fever, lethargy, anorexia, and lymphadenopathy.

E. canis causes canine monocytic ehrilichiosis [11,17]. Diagnosis of Ehrilichiosis is not usually made until

signs of weight loss, uveitis and haemorrhagic disorders become apparent [13]. Ehrilichiosis can cause

severe disease in humans as E. canis is closely related to Ehrlichia chaffeensis which causes human

monocytic ehrlichiosis (HME). This disease is characterised by fever, anorexia, vomiting, and weight loss

[10,18,19,20]. It has been suggested that climate change is contributing to increased geographical

distribution of R. sanguineus to areas previously uninhabited by ticks, thus spreading disease [8]. Ehrlichia

Figure 1 – Tick on the ear of a stray dog brought to the BPT for neutering

5

has been isolated from infected dogs in many countries including Spain, Greece, Egypt, Japan, Africa and

India [20,21,12].

1.3 Anaplasma

Canine anaplasmosis is caused by an intracellular rickettesial organism, two species are considered

pathogenic in dogs; Anaplasma platys and Anaplasma phagocytophilum [14,15]. The latter is considered

more pathogenic and zoonotic with the risk of causing granulocytic anaplasmosis. A. platys is only reported

to cause clinical infection when the animal is co-infected [12]. A. phagocytophilum is spread by Ixodes tick

and infects neutrophils and eosinophils causing fever, anorexia, lethargy. A. platys is spread by R.

sanguineus and mainly infects platelets causing cyclic thrombocytopenia [11,14]. Anaplasma and Ehrlichia

are common in tropical areas and are commonly seen as co-infections [13].

1.4 Borrelia

Borreliosis is caused by spirochaete bacteria transmitted by Ixodes tick [14]. Wormser (2006) reports more

common occurance in the northern hemisphere [22,15]. Borrelia burgdoferi sensu lato is the agent of human

Lyme disease, a severe disease in humans [22,25]. Many of the cases in dogs are seropositive and show no

clinical signs of the disease, although when clinical signs do present they most commonly cause disease in

the nervous system or in joints [10].

1.5 Dirofilaria

Dirofilaria immitis, Dirofilaria repens and Acanthocheilonema spp. cause heartworm disease in dogs, these

have all been reported in India [23]. It is currently thought that D. immitis is confined to northern India,

while D. repens to southern India. In Sri Lanka mosquitoes are very prevalent, this is important as filarial

nematodes tend to be common where mosquitoes are present [15]. Dirofilaria spp. is thought to affect the

lungs and lymphatic system of the animal. [7] It has been reported that the filarial species Brugia ceylonensis

is endemic in Sri Lanka, however is difficult to differentiate from B. malayi [23]. There have been reports of

human cases of dirofilariasis caused by Dirofilaria repens in Sri Lanka [24].

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1.6 Babesia

Babesiosis is caused by an intraerythrocytic prioplasm protozoa from the phylum Apicomplexa [14,15,25]

there are two main species; Babesia canis and Babesia gibsoni [26,17]. Clinical signs include anaemia,

anorexia, pale mucous membranes, vomiting, and jaundice [25]. Disease is transmissible by Ixodid ticks,

primarliy Ixodes scapularis [26,27]. Babesia has zoonotic potential, the two agents causing human

babesiosis are Babesia microti and Babesia divergens, [28] thus confirming diagnosis in dogs has

importance in human health. There is currently no conclusive data on Babesia prevalence in India; the

reported prevalence in dogs ranges between 0.1-22% [26].

1.7 Hepatazoon

Hepatazoon canis and Hepatazoon americium causes canine hepatazoonosis an arthropod-borne infection

[14]. It is suggested to have been present among dogs in India since 1905 [30,31]. H. canis is worldwide and

generally subclinical with dogs appearing healthy; however H. americanum is more confined to the US and

causes severe disease. Rhipicephalus sanguineus is the main tick vector of H.canis. [32]. Hepatazoon is

transmitted differently than other tick-borne parasites; an infected tick must be ingested to cause infection

[10].

1.8 Aims:

The main aim of this study was to evaluate the burden of blood-borne parasites, many of which have

zoonotic potential, in a population of dogs presented to a neutering clinic in Colombo, Sri Lanka, in order to

gain further insight into the prevalence and impact of the above diseases in Sri Lanka.

1.9 Null hypothesis:

i) No difference between neutered or entire dogs positive for tick-borne diseases.

ii) No difference between owned or stray dogs positive for tick-borne diseases.

iii) No difference between sexes of dogs positive for tick-borne diseases.

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2.0 Data collection:

The data for the project was collected from a set population of dogs in Colombo, Sri Lanka. Data was

collected in conjunction with the Blue Paws Trust (BPT), a sterilisation clinic, and neighbouring Pet Vet

Clinic. Colombo was the sole location studied, however the hope was that results collected are transferrable

to the rest of Colombo and possibly Sri Lanka. Dogs sampled were both pet dogs and stray dogs, varying

between completely stray and owned but roaming dogs.

A minimum size of 100 was aimed for, however it was only possible to attain 80 samples in the 2 week

period in October 2014.

The sampled stray dogs were caught and restrained by trained BPT staff with minimum force and stress. The

dogs were clinically assessed by vets at the BPT. The dogs were anaesthetised for surgery before any

sampling was performed; further reducing stress. This project has been approved by the Royal Veterinary

College Ethics and Welfare Committee.

Data recorded:

• Sex of each animal (male, female)

• Neuter status (Neutered, entire)

• Other illnesses – externally identifiable in stray animals as the history will be unknown; clinical

history was consulted for pets.

• Stray or owned (pet-non roaming)

• Breed

2.1 Sampling method:

Blood was collected using a 2.5ml syringe and 21gauge needle from a peripheral vein, either cephalic or

saphenous. Blood was immediately transferred into an EDTA tube and mixed to prevent clotting. Blood

smears were prepared and an IDEXX 4Dx Plus snap test was used.

The blood smear was made as described below see 2.3 method for creating blood smear.

8

IDEXX labs provided 100 4Dx Plus snap tests, these were used to test for Dirofilaria immitis antigen,

antibodys to Anaplasma phagocytophilum, Anaplasma platys, Ehrlichia canis, Ehrlichia ewingii and

Borrelia burgdorferi.

2.2 The method of the snap test:

The snap test was used in accordance to the manufacturer’s instructions. (See appendix)

2.3 Method for creating blood smears

Capillary tubes were used to pull blood from the EDTA tube, a small drop of blood was placed from the

capillary tube onto the microscope slide. Another slide was then used to thinly spread the blood sample into

a bullet shape with a feathered edge. The viscosity of the blood affected the angle of the slide used to spread

the sample; a greater angle was used to spread blood of low viscosity and vice versa. This allows a

consistency in size and length of the blood smears. Blood smears were then air dried and dipped 10 times

into 100% alcohol to fix the slide and organisms. They were then air dried again and placed in the slide box

for transportation. They were stained with a Wright-Gimesa stain which allowed visualisation of bacteria/

parasites in the smear. The blood smears were examined under the microscope using X20, X40, and X100

(oil emersion) lenses.

2.4 Statistical method

SPSS Software version 22 was used to analyse the data. As the results were not normally distributed a

non-parametric test (Chi squared or χ2 test) was used to determine if results were statistically

significant (p<0.05).Fishers exact test may be given due to the small sample size. The population was

9

described using descriptive statistics and examined graphically. Two categorical sets of data were

compared; comparing sex, neuter status and ownership against positive test results.

3.0 Results:

Blood samples were taken from 80 dogs, 40 were from stray dogs at the BPT and 40 were pets from

the Pet Vet Clinic. Canine TBDs were diagnosed in 34 of the 80 dogs sampled; this represents 42.5%

of the population sampled.

3.1 Sex vs snap test result

Graph 1 shows more females were positive on the snap tests than males at 45.5% and 28.5% respectively.

Graph 1 – A bar graph to show the relationship between the sex of the dogs tested and the results of the snap tests.

10

!

There are more negative results in males (71.5%) than females (54.5%). However, statistical analysis

showed no correlation between sex and presence of infection; as determined by a Fishers exact test 0.373,

(p>0.05).

3.2 Diseases and Snap test results:

Number of positive and negative females and

males on the snap tests

Nu

mb

er

of

do

gs

0

13

25

38

50

Sex

Female Male

10

36

4

30

PositiveNegative

Graph 2- A bar graph to show numbers of dogs sampled which were found to be positive for canine tick borne diseases and predominantly which ones by the snap tests.

11

!

Anaplasma and Ehrlichia were the most commonly detected parasites in the tested dog population, see graph

2. Of the population 27.5% (n=22/80) tested positive for Anaplasma and 36.25% (n=29/80) positive for

Ehrlichia. Dirofilaria was uncommon with 1.25% affected (n=1/80). No Borelliosis was detected. Co-

infection with Anaplasma and Ehrlichia was relatively frequent with 23.7% (n=19/80) of dogs testing

positive for both.

Statistical analysis shows an association between positive snap test and Anaplasma (p=0.000), this was

consistant with Ehrlichia.

3.3 Presence of ticks vs snap test result

Results for the snap tests1

N

um

ber

of

do

gs

0

25

50

75

100

Parasites

D. immitis B.borgdoferi A. platys and E.canis

6151

100

58

99

19290221

PositiveNegative

Graph 3 – A graph to compare the number of dogs infected with ticks and infected with canine tick borne diseases

1IDEXX Snap 4Dx Tests

12

!

The majority of dogs did not have ticks detected on clinical exam 60% (n=48/80). Parasites were detected on

snap test in 50% of the population (see Graph 3), whether positive or negative for ticks. Ticks were found on

37.5% (n=30/80) of dogs where no parasitic infection was detected. Statistical analysis revealed no

correlation between the presence of ticks and a positive snap test for any disease tested; Fisher’s exact result

0.356.

3.5 Neuter status vs snap test result

A graph comparing percentages of animals with

ticks and parasites

Nu

mb

er

of

do

gs

0

25

50

75

100

Presence of ticks

Positive Negative

50

304040

48

32

TotalPositive parasites Negative Parasites

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!

Graph 4 demonstrates no relationship between neutered dogs and positive snap tests as equal numbers of

neutered 42.8% (n=9/21) and entire 42.4% (n=25/59) dogs were positive, Fishers exact test 1.000, p>0.05.

3.6 Ownership status vs snap test result

!

Graph 5 illustrates a significantly higher proportion of stray dogs were positive when compared with pet

dogs 57.5% (n=23/40), Fishers exact test 0.012, p<0.05.

3.7 Neuter status vs Ehrlichia and Anaplasma

Negative Positive

Positive snap test

Negative Positive

Positive snap test

Graph 4 – A graph to show the relationship between neuter status (neutered or entire dogs) and their snap test results

Graph 5 – A graph to show the relationship between ownership (stray or pet) and snap test results

Graph 6 and 7 – Bar graphs to show the relationship between neuter status (neutered or entire) and presence of Ehrlichia spp. and

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Statistical analysis revealed no association between Ehrlichia and Anaplasma and neuter status. Of the entire

population studied, 36.25% (n=29/80) were positive for E. canis, whereas only 28.6% (n=6/21) of neutered

animals were positive for E. canis (see graphs 6 and 7). Fishers exact test 0.440, (p>0.05). This was the

same for Anaplasma 28.6% (n=6/21) of neutered animals were positive, fishers exact value of 1.000,

(p>0.05).

3.8 Blood smear pathogens

Blood smear results

Perc

en

tag

e

0

20

40

60

80

Pathogens present

D. immitis H. canis

7673

47

PositiveNegative

Graph 8 – a bar graph to show the presence of canine tick borne diseases on blood smears created from sample dogs.

15

Blood smear examinations were negative for Ehrlichia, Anaplasma and Babesia, however graph 8 shows

Hepatazoon gamonts and Dirofilaria were observed with 5% (n=4/80) and 8.75% (n=7/80) positive

respectively.

4.0 Discussion:

4.1 Presence of disease:

Ehrlichia and Anaplasma

The main aim of this study was to determine the prevalence of canine TBDs in a sample population of dogs

in Sri Lanka. It was determined that the most prevalent disease was Ehrlichiosis (36.25%) followed by

Anaplasmosis (27.5%) and co-infection with both pathogens (23.7%). The result of this study are similar to

that conducted in India by Abd rani et al, 2011 which found H. canis, E. canis and A. platys most common;

with H. canis most prevalent [12]. Transmission of these diseases may be attributed to R. sanguineus, which

is the predominant carrier. R. sanguineus was reported in several studies to be one of the most common ticks

in Sri Lanka and the most abundant tick affecting both dogs and wild animals [8,12]. Interestingly,

Liyanaarachchi et al, 2015 also found Dermacentor auratus, which is thought to transmit Anaplasma platys,

to be the second least abundant tick species in Sri Lanka [8]. These findings are important as it provides

evidence of the presence of canine TBDs in Sri Lanka should lead to further research in this area.

Dirofilaria

We found one positive snap test for Dirofilaria, however microfilaria were found on seven blood smears.

The snap test only detects D.immitis antibodies therefore infection of other Dirofilaria species would not be

detected. The results are surprising as there is a 95% CL for both sensitivity and specificity on the test for

Dirofilaria, therefore it is likely the species found on the blood smear was Acanthocheilonema reconditum or

D. repens, the most common filarial parasite in Sri Lanka. Dissanaike et al, 1997 reported 30-60% of Sri

Lankan dogs are infected with D. repens [24]. Dirofilaria is also thought to be common in Sri Lanka due to

mosquito vectors which are ever present in the country.

Hepatazoon

16

Hepatazoon gamonts were observed on seven blood smears. Its presence in the population can be expected

due to the abundance of R. sanguineus ticks. This finding supports studies which found Hepatazoonosis in

domestic dogs in Sri Lanka [32]. Although Hepatazoonosis causes disease in dogs it is not zoonotic

therefore implications to the BPT are minimal.

Babesia

Although Babesia has been reported to exist in India and worldwide no Babesia spp. were identified in this

study. [26,33]. This lack of evidence could be due to the small sample size and the location constriction, it

has also been suggested that multiple blood smears may need to be examined over several days to identify

the parasites [28]. Identifying Babesia on blood smears is an insensitive diagnostic method. Future research

could look into the use of PCR techniques, serology or cytology to improve sensitivity. [10].

Borrelia

The negative results for Borrelia were a very important finding as this is a serious zoonotic disease. To

improve the reliability of these results a bigger size sample and more locations in Sri Lanka should be

covered. This is of relevance because the ticks that transmit this disease, Ixodes species, are present in Sri

Lanka and reported to infect humans, not wild or domesticated animals [8].

The overall results of this study have few implications for the neuter project itself. However, it must be taken

into account that the pathogens isolated from the dogs included Ehrlichia, Anaplasma and Dirofilaria, all

have zoonotic potential. This means that the workers at the neuter clinic need to be cautious when examining

infected dogs.

4.2 Co-infection

This study supports Abd Rani et al, 2011 in displaying co-infection with canine TBDs is common [12,10].

This could be explained in Sri Lanka due to the main tick species R. sanguineus’ ability to simultaneously

harbour many of these diseases. It is reported to carry Babesia canis, Hepatazoon canis, Ehrlichia canis and

Anaplasma platys [10,11]. A consequence of this is one tick can transmit multiple canine TBDs to one host

weakening the immune system allowing for infection of other pathogens. R. sanguineus is more common in

17

urban areas [12,34], as this study was conducted in Colombo, the capital, it is presumed this is the main tick

affecting dogs tested. Co-infection is an important factor affecting treatment of these diseases [12], therefore

these results could provide reason behind potential treatment failures and shape future treatment plans.

4.3 Ticks

Of the sample population 40% (n=32) were found to carry ticks. A study conducted in Jodhpur, India into

health status of 323 sexually intact stray dogs found a 68% prevalence of ticks [6] indicating higher

prevalence in India. Although there are studies in Sri Lanka on the species of ticks present, there is limited

data on the overall prevalence of ticks on dogs, this is an area for future research.

This study showed no statistically significant relationship between the presence of canine TBDs and the

presence of ticks, this was surprising as correlations were found between these factors in India [12]. This

result indicates other factors may influence infection levels, such as species of tick and tick disease carrier

status. Our results may be affected by small sample size and limited data analysis methods. This study could

be improved by investigating which tick species were found on dogs studied, similar to a study done by

Liyanaarachchi et al, 2015 [8]. This would provide information on which diseases could be infective to BPT

workers and help with tick control/disease prevention. This was not feasible within this project but could be

an area for further study.

4.4 Neuter status vs snap test results

It was hypothesised that more neutered animals would be positive for tick-borne diseases than entire

animals.

No statistically significant relationship was found between neutered dogs and positive canine TBDs results,

p>0.05, supporting the null hypothesis. It is has been put forward by some studies that the sex hormones

play a vital role in the immune system response [35] therefore neutering, and the removal of these, could

cause a decreased immune response subsequently increasing infection risk. However, Kirkpatrick, 1988

demonstrated that gonadectomy decreases the likelihood of parasitism, therefore neutering is not considered

a predilection factor [36]. Abd rani et al, 2011 found neutered dogs were less likely to be PCR positive for

canine TBDs than entire dogs [12].

18

4.5 Ownership status vs snap test results

The second hypothesis was that tick-borne diseases would demonstrate greater prevalence in stray dogs than

pets.

There was a statistically significant relationship between stray dogs and positive canine TBDs results,

p<0.05, rejecting the null hypothesis. It is also thought that stray dogs are more susceptible to infection due

to poor nutrition, being unvaccinated and experiencing higher stress levels. This culminates in a reduced

ability of the immune system to mount an effective response increasing risk of infection [6]

4.6 Sex status vs snap test results

The final hypothesis was that more males would be affected by tick-borne diseases than females.

There was no statistically significant relationship between sex and positive snap test results, p>0.05,

accepting the null hypothesis. Klein, (2000) determined that male animals are more susceptible to

protozoan, fungal, bacterial, and viral infections, this susceptibility may be due to androgens modulating

immunity [37]. However, previous studies into E. canis showed no relationship between seroprevalence and

sex [16]. Our results may have been influenced by the small sample size and sample bias due to more

female participants than males, however it may also be that in this population there is no difference in

immune responses between males and females.

4.7 Improvements

Using the snap tests from IDEXX improved the sensitivity of the results as microscopic examination has

previously been suggested to be of limited sensitivity. No animals showed signs of infection on clinical

examination, therefore finding organisms on blood smear examination and positive snap test results may

indicate a degree of subclinical infection. Improving detection of infection would require use of multiple

diagnostic techniques, a combination of haematology, serology and molecular testing (PCR) to avoid any

misdiagnosis of the presence of parasites.

19

It has been shown by Bohm et al, 2006 and Schetters et al, 1998 that sampling from the ear vein can produce

better results for finding pathogens [38,39]. It is believed that capillary samples are the most diagnostic as it

is thought that the blood moves slower though these veins due to increased red blood cell membrane rigidity,

therefore red blood cells containing parasites congregate here [38]. In this study it was not possible to collect

blood from the ear.

A larger sample size, longer time for data collection and samples taken from different regions of Sri Lanka

would have improved this study. This would have provided more comprehensive results and reliable data

and allowed findings to be more transferrable to the country as a whole. This may be considered an area for

further research.

4.8 Future research

A sample bias existed in this study, all dogs brought to the BPT over the two week period were sampled,

however more data could have been recorded. The age and body condition of dogs could have been

included, although some studies suggest these are not significant risk factors for canine TBDs [12].

There is potential for further research into these factors affecting clinical signs throughout Sri Lanka.

Reduction in disease burden may be achieved by vector control. Townson et al, 2005 reported that in

countries with malaria, such as India and Sri Lanka, disease control programmes focusing on vector control

were highly effective. [1]. Tick control is likely to be difficult in Sri Lanka, as the huge population of

roaming dogs are unlikely to receive treatment or preventative therapy. It may be useful for future research

to examine whether tick control is a viable prevention strategy and its efficacy in preventing canine TBDs.

5.0 Conclusion

This project provides new and interesting evidence into the presence of at least 4 canine tick-borne diseases;

Anaplasma, Ehrlichia, Dirofilaria and Hepatazoon in a population of dogs in Colombo, Sri Lanka. To the

authors knowledge this is an area that has not been studied previously. This study has also proved that co-

infection with canine TBDs is present in Sri Lanka; this should be made aware to practitioners who may be

initiating treatment of canine TBDs. In order to gain a more reliable and comprehensive understanding of

canine TBDs in Sri Lanka further investigations need to be conducted using data from more locations and

with larger sample sizes.

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6.0 Acknowledgements

The author of this study would like to give thanks to the British Veterinary Association for the projects

acceptance of the Overseas Travel Grant 2014. The author would like to thank IDEXX laboratories for

providing 100 snap tests for this project, also to the Blue Paw Trust for allowing samples to be collected and

the neighbouring Pet Vet Clinic for allowing sample collection and use of the laboratory facilities for

sample analysis. Finally the author would like to thank Kate English for all her help with the project.

Word count: 3985

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8.0 Appendix

Please find attached the information sheet for the IDEXX 4Dx Plus snap test.