https://www.galaxydx.com/bartonella-and-the-eyes/

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Cats are not small dogs: is there an immunological explanation for why cats are less affected by arthropod-borne disease than dogs?

Michael J. Daycorresponding author

Abstract
It is widely recognized that cats appear to be less frequently affected by arthropod-borne infectious diseases than dogs and share fewer zoonotic pathogens with man. This impression is supported by the relative lack of scientific publications related to feline vector-borne infections. This review explores the possible reasons for the difference between the two most common small companion animal species, including the hypothesis that cats might have a genetically-determined immunological resistance to arthropod vectors or the microparasites they transmit. A number of simple possibilities might account for the lower prevalence of these diseases in cats, including factors related to the lifestyle and behaviour of the cat, lesser spend on preventative healthcare for cats and reduced opportunities for research funding for these animals. The dog and cat have substantially similar immune system components, but differences in immune function might in part account for the markedly distinct prevalence and clinicopathological appearance of autoimmune, allergic, idiopathic inflammatory, immunodeficiency, neoplastic and infectious diseases in the two species. Cats have greater genetic diversity than dogs with much lower linkage disequilibrium in feline compared with canine breed groups. Immune function is intrinsically related to the nature of the intestinal microbiome and subtle differences between the canine and feline microbial populations might also impact on immune function and disease resistance. The reasons for the apparent lesser susceptibility of cats to arthropod-borne infectious diseases are likely to be complex, but warrant further investigation.

Keywords: Cat, Dog, Arthropod-borne infectious disease, Disease prevalence, Immune system, Immune function, Genetics, Microbiome
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Background

In recent years there has been renewed interest in investigating the epidemiology, clinicopathological mechanisms and phylogeny of the causative organisms of canine arthropod-borne infectious diseases. Molecular and immunological tools have allowed the discovery of novel pathogens, the reclassification of other microorganisms and provided the ability to undertake surveillance studies that track the geographical movement of these agents and their arthropod vectors. Some of these studies are performed from a ‘One Health’ perspective; with the recognition that many of the canine arthropod-borne infections are zoonotic or that the dog may act as a reservoir or sentinel for human infection [1]. As our companion dogs so closely share our lifestyle and indoor environment, there is recognition that control of these diseases must involve strategies to prevent infection in both people and dogs. One of the strongest cases for a One Health approach to these diseases is that of zoonotic visceral leishmaniosis, where prevention of human infection necessitates control of infection in the canine reservoir in addition to management of the sand fly vector [2].

But what of the other important small companion animal species - the domestic cat? The cat is ubiquitous in both developed and developing societies and equally shares the human environment with the dog [3]. Where numbers of small companion animals are estimated, it is clear that there are similar populations of pet dogs and cats living in human households [4–6] and in developing countries there are significant, but unquantified, populations of stray or community-owned dogs and cats. For example, in the USA in 2011 there were an estimated 69 million dogs living in 36.5 % of households and 74 million cats in 30.4 % of households [4]. In the UK in the same year, there were an estimated 11.5 million dogs in 30 % of households and 10 million cats in 23 % of households [6]. But despite the popularity of the cat as a companion animal, there is relatively little knowledge about the prevalence or nature of feline arthropod-borne infectious diseases. Recent reviews cover these infections [7, 8], but it is clear that we understand less about the same agents in cats compared with dogs. Anecdotally, it is often suggested that cats are less affected by arthropod-borne diseases than dogs and that this may be attributed to some form of natural resistance to these pathogens or their vectors. This would appear to be supported by a relatively low prevalence of most infections recorded in cats in areas in which the diseases are endemic [9–12]. The aim of this review is to explore this hypothesis and examine the evidence that underpins this proposal.

Do cats get less arthropod-borne infectious disease and if so, why?
A recent study suggests that the number of zoonoses shared between man and different domestic animal species is determined by the time since that species was domesticated. The dog shares the most infectious diseases with people as dogs were first domesticated at least 15,000 years ago. In contrast, feline diseases shared with man are suggested to be only one third of the number of those of the dog because domestication of the cat occurred 10,000 years ago [13].

If one considers the prevalence of the major arthropod-borne infectious diseases of small companion animals, a ‘broad brush’ perspective would suggest that cats are less affected by these conditions than dogs (Table 1). To assess this in a somewhat more robust fashion, a search of the Thomson Reuters Web of Science database (performed in May 2016) was performed using the search terms ‘dog AND arthropod borne disease’, ‘cat AND arthropod borne disease’, ‘dog AND vector borne disease’ and ‘cat AND vector borne disease’. Between 1997 and May 2016, this search revealed 496 publications for the dog and 175 for the cat, with marked rises in the number of publications related to both species from 2008 onwards.

Table 1
From this link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5028948/

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Many Blessings,
CrystalRiver