Discussion on Etiology and Pathogenesis of Corona Virus Disease 2019 from “Cold-dampness and Insidious Dryness”

LU Fang-Guo, WU TAO, XIAO Wen-Ming, WANG Ping, ZHAO Cheng

a.Medical School, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China

b.Graduate School, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China

c.Hunan Administration of Traditional Chinese Medicine, Changsha, Hunan 410008, China

Keywords

2019 novel corona virus (2019-nCoV)

Pneumonia

Pathogenic pathogens of cold and dampness

Game between healthy Qi and toxic pathogen

Hubei Province

Hunan Province

ABSTRACT

Based on the characteristics of the epidemic situation and the authors’ understanding of the related ancient books and documents, this paper explores the etiology and pathogenesis of Corona Virus Disease 2019 (COVID-19)from 5 aspects: abnormal climate in “warm winter”, unique geographical location,pathogenesis evolution of cold and dampness mixed with insidious dryness, transmission and change of “triple energizer”of toxic pathogens, and game between healthy Qi and toxic pathogens.Combined with the special treatment of traditional Chinese medicine (TCM), the purpose is to make a modest contribution to curbing the epidemic situation with TCM.

1 Introduction

Since December 2019, corona virus visease 2019,(COVID-19)in Wuhan City, Hubei Province has caused great harm to the society and the public.By 24 : 00 on March 17th, 2020, a total of 81 151 cases of COVID-19 have been confirmed, 3 242 cases have died, and 69 725 cases have been cured and discharged from hospital.The disease belongs to the category of “epidemic disease” or “plague” in traditional Chinese medicine (TCM).Its core pathogenesis involves “cold-dampness epidemic”“Qi failing to control body fluid” “dampness-toxin epidemic”, etc.[1-3].Based on the characteristics of the epidemic situation and the authors’ understanding of the relevant ancient books and documents on the epidemic situation, this paper probes into its etiology and pathogenesis, hoping to make a modest contribution to curbing the epidemic situation with TCM.

2 Abnormal Climate of "Warm Winter"

Meteorological data found[4]: warm winter climate occurred in Wuhan city, Hubei Province in the middle and first 10 days of December 2019.The specific conditions were: from December 1st, 2019 to December 16th, 2019, the highest temperature was 8 -18 °C and the lowest temperature was 0 - 9 °C.Except for light rain on December 16thand northerly wind of level 3 - 4, the remaining 14 days were mainly sunny or sunny to cloudy, with breeze and weak wind force.The not cold climate in a cold season provides conditions for the breeding and spread of the current virus (epidemic pathogen).After that, the lower temperature and humid climate in this area provided conditions for the survival of epidemic pathogen(temporal virus).From December 17th, 2019 to December 31st, 2019, the highest temperature in this area was 5 - 13 ℃ and the lowest temperature was 0 -6 ℃.Except for sunny or sunny to cloudy weather and breeze on December 26th, 27thand 30th, light rain or cloudy to light rain weather and breeze dominated the remaining 12 days.Most viruses (current viruses and epidemic pathogens), including 2019 novel corona virus (2019-nCoV)which is cold-resistant have a relatively long survival time in low temperature and humid environment.Therefore, the low temperature and humid climate during this period also provide conditions for the development of the epidemic.On the Origin and Syndrome of Various Diseases, Seasonal Epidemic(Zhu Bing Yuan Hou Lun · Shi Qi Hou, 《诸病源候论 · 时气候》)said:“Those seasonal epidemics often occur at abnormal weather and climate like cold spring, chilly summer,hot autumn and warm winter.During a year, when pathogens appear in wrong seasons, many people despite the age will catch similar diseases.This kind of disease is called seasonal epidemic.” Therefore, it can be seen that climate change in nature should keep in line with the pace of seasons.Only when human physiological changes conform to nature can they maintain a healthy state.Otherwise they are prone to diseases.Plain Questions,Principle of Six Climatic Factors(Su Wen · Liu Wei Zhi Da Lun, 《素问 · 六微旨大论》)also recorded: “The emperor said:‘What will happen when right weather and climate fall in wrong season?’ QI Bo said: ‘Right weather and climate leads to goodness, otherwise, wrong weather and climate leads to bad changes.Bad changes end up with illness.’ ” This shows that the abnormal climate of “warm winter” in Wuhan City, Hubei Province in the middle and early December 2019 is closely related to the occurrence of infectious pneumonia of 2019-nCoV.

3 Unique Geographical Location

Wuhan is located in the eastern part of Jianghan Plain, with river networks and interwoven lakes and ports in the boundary.The water area accounts for a quarter of the city’s total area, making the area rich in moisture.People in the territory have lived in wetlands for a long time.They are susceptible to external humidity.Warm humidity is submerged in the body.When it coincides with the “warm winter”in December 2019, water turns into humidity, cold and dampness are mixed and combined to become diseases.Therefore, the unique geographical location is also an important reason for the formation of dampness pathogen.

On Typhoid Fever(Shang Han Zhi Zhang,《伤寒指掌》)said: “When it rains for a long time, dampness is rampant.Spleens are affected and people are mostly prone to cold and epidemic.”Re-defining Popular Treatise on Typhoid Fever(Chong Ding Tong Su Shang Han Lun,《重订通俗伤寒论》)pointed out:“Cold epidemics occur frequently in April, May, June and July.If the weather is often rainy, dampness will be rampant.Typhoid fever is usually accompanied by dampness[5].” It can be seen that the abnormal climatic conditions of "warm winter" (wrong weather and climate)and unique geographical location work together, making Wuhan a hotbed for the breeding and spread of the “cold and wet epidemic”.

Hunan Province and Hubei Province are located in the central and southern regions of China.They are adjacent provinces to each other.The climatic conditions of the two provinces are relatively close.In December 2019, the highest temperature in Changsha City, Hunan Province was 8 - 23 ℃ and the lowest temperature was 2 - 9 ℃.In the first 10 days of December, the weather was mainly sunny or sunny to cloudy, while in the middle and later 10 days, it was mainly light rainy or overcast to light rainy.In the 31 days of December, the wind direction was northerly and the wind force was breeze for 20 days, of which the wind force on December 25thand 31stwas northerly and of level 3 - 4[6].As COVID-19 is mainly transmitted through respiratory tract and Hunan Province is located in the area south of Wuhan City,Hubei Province, the north wind direction and certain wind force provide conditions for the spread of the current virus or epidemic pathogen from Wuhan City, Hubei Province to Hunan Province.Therefore,shortly after the outbreak in Wuhan City, Hubei Province, a new type of pneumonia epidemic occurred in Changsha City, Hunan Province.The situation of prevention and control was serious.By 24 : 00 on March 17th, 2020, Hunan Province had reported a total of 1 018 confirmed cases of COVID-19.

4 Pathogenesis Evolution of Cold-dampness Mixed with Insidious Dryness

The main pathogenesis of this disease is the mutual accumulation of cold-dampness epidemic pathogen and insidious dryness (cold-dampness is wrapped in the outside and insidious dryness lurks in the inside),choking the chest and lung.Cold-dampness and epidemic pathogens mingle with insidious dryness and enter into the body from the mouth and nose,resulting in abnormal ascending and descending of Qi activity.The lung governs the promotion and reduction of Qi activity and regulates water channels.If the lung Qi is lost, the lung Qi will choke up the chest.Cold-dampness epidemic pathogen suppresses lung Qi and does not make it spread out.If the lung fails to work normally, the Qi in the whole body will lose their track.The inversion of lung Qi cannot help the heart to circulate blood, which makes the blood collaterals in the lung unable to effectively exchange subtle substances in the blood and leads to dyspnea, hypoxia, etc.In addition, due to the mutual influence of insidious dryness and cold as well as dampness, the disease presents compound symptoms of dryness and dampness, such as dry cough and thick and greasy tongue coating.Dryness is dry and astringent.Lung Yin is damaged for a long time, so the main symptom is dry cough.The cold and hot properties of insidious dryness itself are not obvious.Cold dryness represents dryness mingling with cold, while warm dryness represents dryness mixing with heat.Therefore, when considering the evolution of the disease, the factor of insidious dryness cannot be ignored.The compound symptom of dryness and other pathogens should also be considered.

According to the theory of “epidemic disease taking a round of 3 years to break out” based on the 5 evolutive phases and 6 climatic factors in TCM, 3 years ago was Dingyou’s year (2017).Plain Questions,Acupuncture Technique(Su Wen · Ci Fa Lun,《素问 · 刺法论》)said: “Dingyou’s year lost its position and… Epidemic disease occurs in three years.” The winter of 2019 is dominated by the 6thclimatic factor at the end of the year of Jihai.Plain Questions,On Six Climatic Factors in Sixty Years(Su Wen · Liu Yuan Zheng Ji Da Lun Pian,《素问 · 六元正纪大论篇》)recorded: “At the year of Jihai, ..., the characteristics of the 6thclimatic factor are that it fears dryness and likes dampness.At that time, Yang dominates,dormant insects appear, the running water is not icy,the earth is full of Qi, the grass is growing and people are comfortable.The disease combines with dryness.” At the end of Jihai's year, the earth phase is not good, Yang Qi could not be effectively sealed.Instead, there were abnormal weather like “warm winter” with features such as “dormant insects appear, running water is not icy, the earth is full of Qi,and grass is growing”.Yang Qi leaks out.The subsequent dryness damages Yin.Lung is a delicate viscera, which cannot resist cold and heat.Dryness pathogens are most likely to damage the lung and lurk in the lung collaterals, which is also consistent with the symptoms of “fever and dry cough” in this epidemic.

5 The Transmission and Change of Toxic Pathogen in "Triple Energizer"

In terms of lesion site, the upper energizer of lung is center, but it can be transmitted to the middle energizer of spleen and stomach.Among critically ill patients, “reversed transmission to pericardium”occurs.It may lead to disease of the lower energizer of liver and kidney.According to the research paper published in the Lancet[7], there are some symptoms:cough (82%), shortness of breath (31%), muscle pain(11%), headache (8%).It can be seen that lung is the most important site of onset.In addition, frontline experts on the epidemic situation[1,3]found that most of their patients were accompanied by spleen and stomach symptoms such as vomiting, evil and poor appetite, which shows that spleen and stomach are also important pathogenic parts.The “Diagnosis and Treatment Plan for Pneumonia Infected in Novel Coronavirus” (4thEdition for Trial Implementation)published by the General Office of the National Health Commission and National Administration of Traditional Chinese Medicine points out that in the early stage of clinical treatment of the disease, light patients only show low fever, slight fatigue, etc., and no pneumonia.Continued development will lead to typical manifestations such as fever, dry cough and fatigue, some accompanied by digestive tract symptoms.Severe patients are affected with dyspnea and/or hypoxemia, acute respiratory distress syndrome, septic shock, difficult to correct metabolic acidosis and coagulation dysfunction, etc.[8].From the change of the disease condition, we can know the influence of the “triple energizer” transmission and even the “reversed transmission to pericardium” of the pathogenic factors.

From the changes of its clinical manifestations, it can also be confirmed that the development of the disease has stages and its course evolution is not as rapid as that of the pathogenic heat.Its incubation period is long.The average incubation period of infection is 5.2 d (95% confidence interval is 4.1 to 7.0)and the 95% distribution point is 12.5 d.Progress is from surface to interior, from shallow to deep, from light to heavy and from reality to emptiness.

6 Game Between Healthy Qi and Toxic Pathogens

The occurrence and development of “epidemic disease” or “plague” depends on the game results between the body’s immune system (healthy Qi)and exogenous epidemic pathogens (toxic pathogens).The manifestations of COVID-19 in each stage of clinical treatment are closely related to the depth of the body’s perception of toxic pathogens and the normal lung health function.In the early stage (colddampness piles up in the lung and dryness injures lung Yin), due to the initial onset of cold-dampness epidemic pathogenic factors, the pathogenic factors are located in Weifen.Dampness pathogenic factors and dryness pathogenic factors invade the surface and there may be no obvious fever, which is characterized by “body heat does not rise”.Therefore, there are clinical manifestations of fever with severe coldness or no fever.It also causes dry cough due to dryness and lung injury and chest tightness due to lung Qi loss.Therefore, there are clinical manifestations such as dry cough and dry throat.At the same time, stomach is the reservoir of food and drink and spleen is a damp viscera.The pathogenic factors of cold and dampness are most likely to invade the spleen and stomach.Therefore, it is also common to see internal dampness symptoms such as chest and epigastric tightness, nausea, poor appetite, loose stool, white and greasy tongue coating, etc.In the middle stage (epidemic toxin closes lung and intestine dryness and fluid deficiency), due to cold-dampness epidemic pathogen entering qifen, dampness pathogen stagnates for a long time and turns into heat, frying body fluid.The pathogen changes from colddampness to dampness-heat or dampness toxin.Therefore, there are clinical manifestations of dampness toxin accumulation like epidemic toxin closing lung.The specific symptoms are less phlegm or yellow phlegm, chest tightness and abdominal distension, constipation, red tongue, yellow greasy or dry coating, slippery pulse, etc.In the severe period(internal obstruction and external detachment), due to deficiency of body Yang, epidemic toxin invades the internal body; pathogenic factors are rampant while healthy Qi is weak and various syndromes appear.Damp-heat foul turbidity turns into dryness,damaging nutrient-blood and Yinfen.Yin injures Yang.The symptoms are cold limbs, purple and dark tongue, thick and greasy tongue coating or yellow dryness, floating and large pulse without roots,phlegm and turbidity covering the pericardium,resulting in faintness, dysphoria and delirium.The symptoms have become internal obstruction and external detachment.In the recovery period(deficiency of lung and spleen Qi)and the later stage of epidemic disease, toxic pathogen are removed while healthy Qi is weak after the game between the two.There may be a series of clinical manifestations caused by deficiency of both Qi and Yin, lung and stomach Yin injury or deficiency of both lung and spleen[8].

7 Special Treatment of TCM

The epidemic has existed since ancient times.There have been more than 300 large and small incidents in Chinese history, but the current epidemic is unprecedented.In ancient times, the epidemic relied mainly on Chinese medical treatment.Compared with western medicine, TCM is “one person, one diagnosis”.It has different prescriptions, high flexibility and strong pertinence for different patients,different symptoms, and different periods.Early intervention of Chinese medicine can shorten the average hospital stay of patients, which is conducive to the rational and efficient use of medical and health resources that were already scarce during the epidemic prevention and control period.By 24 : 00,March 17th, 2020, a total of 1 018 cases have been confirmed in Hunan Province, of which 981 cases had TCM participating in the treatment, accounting for 96.37%.A total of 1 014 cases were discharged from the hospital, of which 981 cases had TCM participating in the treatment, accounting for 96.75%.From the improvement in symptoms of discharged patients after treatment with TCM, among the 981 discharged patients, 692 patients had significantly improved symptoms, accounting for 70.54%; 287 patients had improved symptoms, accounting for 29.26%; 2 patient had no improvement, accounting for 0.2 %.

8 Conclusions

To sum up, the etiology and pathogenesis of the occurrence and development of infectious pneumonia in novel coronavirus are related to the abnormal climate of “warm winter”, unique geographical location, the pathogenesis evolution of cold and dampness mixed with dryness, the transmission and change of “triple energizer” of toxic pathogens, and the game between healthy Qi and toxic pathogens.According to its etiology and pathogenesis, it is a problem worth thinking about and further exploring to prevent the occurrence of epidemic situation in line with time and place, to block the evolution of pathogenesis and the transmission of toxic pathogens based on syndrome differentiation and special treatment of TCM and to strengthen the protection of healthy Qi and enhance the body’s disease resistance.

Acknowledgements

We thank for the funding support from the National Natural Science Foundation of China (No.81774126),Hunan Provincial Innovation Foundation for Postgraduate (No.CX2018B481)and Program for First-class Disciplines of Hunan Province in the Direction of Traditional Chinese and Western Medicine (No.2018ZXYJH20).

Competing Interests

The authors declare no conflict of interest.