Discussion
To help further understand COVID-19 infection and treatment, we studied
64 cases in Wenzhou. The epidemic information showed obviously that
COVID-19 could spread from person to person, having family and community
aggregation, which may cause public transmission. The result was in
keeping with a familial cluster report [16]. We have 25 cases of
Gen.2, a little less than Gen.1 (33 cases), which meant Wenzhou were
still facing the press of importing cases, and the epidemic of local was
still a potential threat that needed to pay attention. Regardless, the
number of cases increase slowly donated to the strategy of city blockade
that made by the government from Jan 25th and Feb
2nd [17 18].
In our cases, the majority cases (58, 90.63%) were ranged from 20–60
(median age was 44), few (5, 7.81%) were above 60. It was inconsistent
with the cases reported in Wuhan[19 20], but similar to
Korea[21]. The reasons were various: the aged had low immunity
compared to the youngers and Wuhan had a great number of elders; the
breakout of COVID-19 in short time challenged the hospital resource,
while the cases we had in Wenzhou were imported by travelers transmitted
from Wuhan or spread by close contacting to them, the main of those were
young and middle aged; genomic and infectivity of virus may evolve after
outbreak; furthermore, we may not be clear to the virus in early phase
for information lacking. Notably, we reported the minimum age of patient
with 26-months old, who got virus from mother, the pre-minimum age was
reported as 6 months [22]. Thus, the whole population may be
susceptible to COVID-19.
There were 51 light cases, 11 severity and 2 critical in 64 cases, no
death. About half had basic disease, especially hypertension; the elders
or with basic disease may have more serious conditions. Most cases (59,
92.19%) had fever, the average temperature was 38.1℃. Temperature was
shown to have correlation to disease severity. Respiratory symptoms were
seen in 45 cases (70.3%), as 28 (43.8%) had gastrointestinal symptoms.
Above half (39, 60.9%) had Weakness, few (5, 7.8%) had muscular
soreness. Importantly, 5 cases had no fever, just with mild symptoms
like cough, pharyngalgia, stuffiness or nausea, but PCR tests were
positive. One case even did not have any symptom. Among these 5 cases, 3
were definite as Gen.1, 2 were Gen.2, the latency of them ranged from
1-14. This important information indicted that the COVID-19 could be
infected with no symptoms, and the latency of COVID-19 could be up to 14
days without showing any typical or obvious symptoms. COVID-19 was so
craft that it may conceal in health groups, and had much more
infectivity than SARS, it may probably cause pandemic, infecting more
population than SARS absolutely.
All 64 cases were tested to be PCR positive in an interval more than 24h
in respiratory samples (sputum or throat swabs). Although nucleic acid
of PCR test had high specificity, due to the unclear course of infection
and skill required to take swab samples, the sensitivity was not
satisfied with only 30-40% in suspect patients (47.4%, 9/19)[23].
But it was showed by the lab information that the virus copies could be
tested to reach highest at 7th day after disease onset. It was reported
that in diagnosed cases, the virus could also be detected in 10%
patients’ blood samples at acute period and 50% of feces[24].
Another report showed 88.9% (8/9) stool sensitivity while blood and
urine were negative[23]. Saliva also had 91.7% (11/12) positive in
diagnostic patients[25]. The PCR positive rate was highly depending
on the sample quality and course of infection. Another problem was the
safety. The doctor faced high infectivity risk during obtaining sample.
And PCR test have its longtime cost disadvantage as well. Compared to
PCR, chest CT was much more convenient and safety. In our study, 62
cases had varying degrees of lung symptoms by checking with chest CT,
Pneumonia (62, 96.9%), Both lungs involvement (61, 95.3%),
Ground-glass opacity (48, 75%), and Consolidation (42, 65.6%). One of
two cases having no lung changes in CTs but had high fever as 38℃; the
other one did not show any symptoms. Cases with normal CT and PCR
positive had also been reported[26 27]. Thus, chest CT and PCR of
nucleic acid shall be combined considered in clinical high suspicion.
Besides, a few patients had rhythm and wave changed in their
electrocardiography that may be caused by low potassium ion under the
attack of virus.
It was also found that patients may have many lower indexes including
WBC, LC, PLT, K+, Na+, OI, and high LDH, CRP, D-dimer (Figure
2 ), BNP and TNI were normal, consistent with a report of multi-center
study[26]. Correlation analyzation showed that the severity had
positive correlated to age, temperate, LDH, D-dimer and negative to LC
and OI (Table 3, Figure 3 ). LDH and LC were good biomarkers for
monitoring progress of disease in all classifications (Figure
5 ). The low potassium may be caused by feed less when fevering or
vomiting, diarrhea by antivirus drug use, and would have influence with
weakness, dyspnea. Thus, it was important to correct low potassium and
keep a close obvious on it during treatment.
The average of hospital stay was 25.8 days, the temperature of fevers
returned to normal with treatment in 1-5 days (2.7 days as average), 20
were discharged when data were collected. The average of COVID-19
nucleic acid test transforming to negative was 12.8 days. In early
phase, the infected lungs presented changes like ground-glass, cloud
turbulence or paving stone pattern, then developed as consolidation
within more than 2 leaves later, having local pulmonary fibrosis if
deteriorated. The inflammation could be absorbed in about 7-10 days if
treated well. The triple therapy (Interferon, Lopinavir/ritonavir,
Abidor) was confirmed to be effective in treating COVID-19 infection.
Weakness and diarrhea during treatment may be related to virus attack or
Lopinavir/ritonavir taken.
ACE2, Angiotensin I Converting Enzyme 2, was confirmed to be the cell
entry receptor of COVID-19 as SARS-CoV[28]. The protein was
expressed in endothelial cells, arterial smooth muscle cells, lung
alveolar epithelial cells, lymphocyte, heart, kidney, testis, ovary, and
gastrointestinal system[29]. It explained why COVID-19 could be
detected in samples of respiratory and gastrointestinal system and blood
as SARS[2] and lymphopenia caused. It also reminded us COVID-19 may
have influence on sterility as SARS, needed to call attention. High
expression of ACE2 was also related to hypertension and smoke, accord
with the vulnerable and high mortality to elders, smokers and those who
had basic disease of hypertension. The protein was involved in
regulating of calcium-activated potassium channel activity by related to
CALM1, CALM3, CHRNA9 and CHARNA10 (String Database), leading to low
potassium in patients infected with COVID-19 and SARS, that may result
in weakness, dyspnea and rhythm.
Due to close relative genomic and same virus receptor ACE2, COVID-19 had
similarity clinical features to SARS, such as fever, high temperate,
respiratory and gastrointestinal system mainly involved, similar chest
CT change, low potassium, low LC, low OI, high LDH and so on. Most of
infection were light cases, suggested that it was milder than SARS. But
had much stronger infectivity, with high infectivity when in latency
without any symptoms. Early diagnosis and treatment when symptom showed,
would bring it a better outcome. We shall do a good
job in public health management,
strengthen health publicity and education to control further spread of
the epidemic as possible. With the experience in handling SARS, we have
confidence and do will defeat the COVID-19 in the end.