#MSCOVID19: Animals to the Rescue

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The other day I mentioned the similarities between the Loo Rolls going from shelves and the issue that the white cells may be accumulating in the lung. However one of the readers pointed out the paper below, and like any good scientist you should not get wedded to any idea and you have to change as new information appears and incorporate it into your world view

The Novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Directly Decimates Human Spleens and Lymph Node Chen Y et al. MedrXiv doi: https://doi.org/10.1101/2020.03.27.20045427

In post-mortem studies it looks like the virus is targeting the spleen and lymph nodes, so good news would be that you MS should go away if you become and severely affected. However an implication could be that the cells are not in the lungs but are not geting to the blood.

However, it seems that it is targeting the macrophages rather than the T or B cells, or perhaps the macrophages are eating the virus. However this appears to be associated with lymphocyte reductions. This may be because the macrophages secrete tumour necrosis factor and IL-6 and this may promote lymphocyte suicide. Drugs use in arthritis block both of these cytokines do people with arthrits do better thatn others after covid infection?

In addition the other day I was taking ProfK to task to suggest that Pangolins (Animal artechokes)were a reservoir for COVID-19 virus not cats as he suggested.

There have been media reports that cats may be a reservoir.

Mallapaty. Coronavirus can infect cats — dogs, not so much

So they have been infecting Ferrets…so bad news for all the Ferret down the trouser loving Northerners. Actually Ferrets have long been used for Flu research. They also infected cats. However they did not find the virus in the lungs but the guts and in species like the mouse the receptor is expressed most highly in the intestine. So beware of cat Pooh. Other studies suggest the virus may be able to infect these species and cats from Wuhan had antibodies , however some people question the infection and cats lick there fur alot and humans are sneezing and the virus gets on the fur, so remember to wash you hands when stroking your cat as you may be wiping your neighbour’s nose-juice on yourself…Keep Safe

However, there is a suggestion that when you look at the ACE2 receptor through which it infects has similarities not with snakes or birds but cattleand hamsters. Now it does not say that this came from cattle or hamsters but does suggest they could be infected.

SARS-CoV-2 spike protein favors ACE2 from Bovidae and Cricetidae. Luan, Jin X, Lu Y, Zhang L. J Med Virol. 2020 Apr 1. doi: 10.1002/jmv.25817. [Epub ahead of print].

This could of course be bad news is we had “Mad Cow” now becoming “Bad Cow” Disease..at present this is a theorectical. But CoVID-19 has essentially grounded planes…what next silencing “Cow Farts”…maybe it is the EcoVirus…China’s contribution to stopping global warming:-)

However it looks like our friend Hammy the Hamster may come to the rescue as an animal model.

Luan J, Jin X,Lu Y , Zhang L Simulation of the clinical and pathological manifestations of Coronavirus Disease 2019 (COVID-19) in golden Syrian hamster model: implications for disease pathogenesis and transmissibility. Chan JF, Zhang AJ, Yuan S, Poon VK, Chan CC, Lee AC, Chan WM, Fan Z, Tsoi HW, Wen L, Liang R, Cao J, Chen Y, Tang K, Luo C, Cai JP, Kok KH, Chu H, Chan KH, Sridhar S, Chen Z, Chen H, To KK, Yuen KY. Clin Infect Dis. 2020 Mar 26. pii: ciaa325. doi: 10.1093/cid/ciaa325. [Epub ahead of print]PMID: 32215622

RESULTS: The Syrian hamster could be consistently infected by SARS-CoV-2. Maximal clinical signs of rapid breathing, weight loss, histopathological changes from the initial exudative phase of diffuse alveolar damage with extensive apoptosis to the later proliferative phase of tissue repair, airway and intestinal involvement with virus nucleocapsid protein expression, high lung viral load, and spleen and lymphoid atrophy (Just like the humans) associated with marked cytokine activation (Just like the humans) were observed within the first week of virus challenge. The lung virus titre was between 105-107 TCID50/g. Challenged index hamsters consistently infected naïve contact hamsters housed within the same cage, resulting in similar pathology but not weight loss (a sickness behaviour). All infected hamsters recovered and developed mean serum neutralising antibody titre ≥1:427 fourteen days post-challenge. Immunoprophylaxis with early convalescent serum achieved significant decrease in lung viral load but not in lung pathology. (So it says it may ne useful for a vaccine responses but not for those already infected) No consistent non-synonymous adaptive mutation of the spike was found in viruses isolated from infected hamsters.

CONCLUSIONS: Besides satisfying the Koch’s postulates (Search the Blog ProfG has talked about these before), this readily available hamster model is an important tool for studying transmission, pathogenesis, treatment, and vaccination against SARS-CoV-2.

However importantly when we look in the lungs there are mononuclear cell infiltrates, thus which the damage to the spleens and lymph nodes could well contribute t drops of lympocytes in the blood, they are still indeed leaving the blood to get into the Lungs

Macrohages (Horseshore nucleus as seen in circled cells , it the 4 day samples some of the cells look lymphocytic (blue nucleas with not my cytoplasma pink bit around the nucleus

Therefore emptying of the blood of lymphocytes will involve both processes including migration out of blood into tissues and loss of cell from the lymph glands not replacing what is leaving the blood.

So it looks like you have an animal systme to test some ideas

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