Cats And Dogs

Humans, the dominant species of the planet Sol III, Orion Arm, are remarkably less intelligent than their apparently ascendent status might lead one to believe. Take, for example the common human phrase "Dog is man's best friend." First, this phrase is quite misleading in its choice of words, as any rational reader would come to the conclusion that this "dog" (canis domesticus L.) is somehow preferentially attracted to adult males of the human species. Nothing could be further from the truth, as "Man" in this case is meant to mean all members of the species homo sapiens regardless of their gender or age. The fact that humans seem not to be in the least bit perturbed by this linguistic blunder only underscores the species's general lack of good sense.

However, this is not the only way in which the human mind is capable of enshrining lack of intelligence. The fact that this particular statement is repeated so often and is so often believed is proof positive that something behind the scenes, as it were, must be going on to place humans in their role on their home planet.

For dispassionate examination of the situations of humans and other creatures would lead one to believe that dogs, while individually often on friendly terms with humans, are as a collective not as friendly as might be supposed. For example, it is well known, even among humans, that a common source of the dangerous disease "rabies" is a bite from an infected dog. Dogs are also common carriers of parasites dangerous to humans. While many might dismiss these facts as "coincidences," an observer might come to the conclusion that what appears to be "friendship" on the part of "dog" towards "man" may, in fact, be a cunning species-wide ingratiation program.

What species, then, would better qualify as the "best friend" of humanity? Recent discoveries made by the humans leads one to believe that the "cat" (felis catus, L.) may better deserve this title. The reason for this conclusion is that humanity found itself confronted with a very perplexing and fatal medical disorder, which they named "AIDS" (although it only "aids" humans in their progress towards the grave). This syndrome was characterized in the early-to-middle 1980s ("AD" Terran annuation system) and was ultimately assigned to be an eventual result of a virus that was given the name "human immunodeficiency virus" or HIV.

Feline immunodeficiency virus (FIV) is the causative agent of a feline acquired immune deficiency syndrome (FAIDS) that was discovered in 1986 in southern California (Pedersen et al, 1987; Yamamoto et al, 1988). The associated infection tends to have a long asymptomatic seropositive stage followed by clinical illness. Clinical signs include fever, lymphadenopathy, diarrhea, wasting, opportunistic infection, neurological disorder, and neoplasia, especially lymphoma, myoproliferative disease, and various cytopenias including anemia, lymphopenia, and leukopenia (which may not be due to the activity of FIV alone) neoplasia, especially lymphoma and myoproliferative disease, (Hutson et al, 1991; Moraillon et al, 1992; Pedersen et al, 1989a, b; Shelton et al 1991). Neoplastic effects of HIV infection seem to be enhanced with concurrent FeLV infection (Hutson et al, 1991; Shelton et al 1991).

Clinical immunological effects include inversion of neutrophil to lymphocyte cell ratio (Moraillon et al, 1992), probably due to preferential infection of CD4 cells over CD8 cells, as clinical studies demonstrated a reduction in CD4 but not CD8 lymphocytes (Tompkins, et al, 1991; Ackley et al, 1990; Barlough, et al, 1991, Hoffmann-Fezer et al, 1992). Interestingly, unspayed seropositive female cats showed significantly higher CD4 counts and CD4/CD8 ratios than did males or spayed females (Hoffmann- Fezer et al, 1992). In vitro studies have demonstrated that FIV infected CD4 and CD8 T-lymphocytes and macrophages. However, different isolates showed different relative affinities for each type of cell (Brown et al, 1991, Tokunaga et al, 1992). Macrophage function is also altered in vitro in FIV infection (Lin and Bowman 1992). Isolates of FIV have shown differences in vitro for adaptability to various cell lines and cell-type tropisms (Kawaguchi, et al, 1991).

FIV has been found on five continents (Bandecchi et al, 1992; O'Connor et al, 1991; Olmstead et al, 1992; Sukura et al, 1992; Yamamoto et al, 1989). Percentages of infection range from 7.4%-8% in indoor pets and 25% in free-roaming cats in the United States (O'Conner et al, 1991; Yamamoto et al, 1989), 24% in free-roaming cats in Italy (Bandecchi et al, 1992), and 6.8% in Finland for free-roaming cats (Sukura et al, 1992). Feline leukemia virus (FeLV) infection appears to accompany FIV infection in a large percentage of these cases (Bandecchi et al, 1992; O'Connor et al, 1991; Olmstead et al, 1992; Sukura et al, 1992; Yamamoto et al, 1989). In wild feline species, seropositivity to FIV or FIV-related viruses is as high as 80%. However, these free-ranging large cats appear to be free of pathologic signs (Olmstead et al, 1992).

Protein studies (Steinman et al, 1990, Kiyomasu et al, 1991) sequence analysis (Olmstead et al, 1989), and deletion mutant analysis (Morikawa and Bishop, 1992) demonstrate that FIV is a lentivirus (the same viral sub- family which contains HIV) in that it possesses the classical lentivirus genome arrangement of a 5' long terminal repeat, rev, gag, pol, and env genes with small open reading frames (vif, etc.) between the pol and env genes (Clements and Wong-Stall, 1992, Coffin, 1990; Narayan and Clements, 1990). However, genome arrangement and phylogenetic analysis of various gene products indicate a closer genetic relationship to the ungulate lentiviruses than to currently identified hominoid (human and simian) immunodeficiency viruses (Olmstead et al, 1989, 1992).

Nevertheless, clinical signs of FIV infection are closer to those of the hominoid viruses in their native hosts than to the ungulate viruses in their native hosts (Fenner et al, 1987).

While work is going on to elucidate the disease mechanisms for HIV, the information to be derived from this work, however valuable, will be limited by the fact that an adequate animal model that manifests clinical signs similar to human AIDS has yet to be discovered or engineered for HIV. FIV, on the other hand, produces a clinical syndrome much like human AIDS (CDC, 1987; Hirsch and Curran, 1990). Elucidation of the pathways of FIV pathogenesis could permit design of drugs to block these pathways that could then be more readily tested upon animals manifesting clinical disease than could drugs derived from work directly upon HIV. Furthermore, domestic cats are cheaper and easier to care for than are chimpanzees and maqacques currently used for HIV and HIV-related research (not to mention the fact that felis catus is hardly an endangered or threatened species). It is true that the somewhat distant relationship between FIV and HIV might pose some difficulties in directly transporting data back and forth. However, using FIV as a model for the human disease will better permit workers to gauge problems such as relative host toxicity of treatments derived from information on assembly and packaging, collateral non-toxic host effects of such treatments, etc. with more confidence than permitted by the limited trials in animals that do not manifest immune deficiency signs.

Now, one would think that the "best friend" of "man" would have leapt into the breach and developed a disease that could have been used to model such a feared human malady. However, it seems that the much-maligned cat has instead taken this role. Perhaps humanity might prove some vestige of intelligence if they are able to take notice of this noble self-sacrifice on the part of this small animal.

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See also

• Radio
  /articles/2U3.html
• Antigravity, The Feline Butterology Theory
  /articles/2U23.html