A few weeks ago, I was interviewed about COVID-19 in West Africa with a focus on the upcoming rainy season.
COVID-19 has ravaged most of the world, with the largest number of cases in the United States. South America and Brazil in particular has become the Epicenter of COVID-19 and India is now becoming a new epicenter and at #4 for the total number of cases behind the US, Brazil, and Russia.
In the United States, the black community has suffered the burden of COVID-19 mortality, and confounding issues related to hypertension, obesity, diabetes and cardiovascular disease have played a role in mortality.
What is the role of the environment in the increase of COVID-19 and COVID-19 mortality? Over the past two months, a number of articles and presentations have examined the roles of seasonality and air pollution on COVID-19 in China, Europe, and the United States. Those results have pointed to pollution as a potential factor in COVID-19 mortality. Particulate matter and NO2 which is a pollutant often found in urban areas where automobile traffic this short-lived pollutant. However, particulate matter, especially PM2.5 has also been linked to COVID-19 deaths. a study under review shows that an increase of 1 microgram/meter cubed of particulate matter leads to an eight percent increase in COVID-19 mortality. Furthermore, earlier studies show the highest mortality in African Americans over 65 due to air pollution; African Americans also live near sites where the burden of pollution is much higher than for whites. Some of this is definitely tied to historical and environmental racism in the United States.
https://www.nationalacademies.org/event/05-28-2020/basc-session-on-air-quality-climate-variability-and-covid-19
SubSaharan Africa has experienced the smallest number of cases relative to the rest of the globe. But is this about the change????
There are several reasons to be worried:
1. The hospital infrastructure in much of Africa is much weaker than the US;
2. Coastal West and Southern Africans share the same DNA pool as the African Americans and Afro-Brazilians with likely similar risk factors leading to COVID-19 mortality;
3. Many of the noncommunicable diseases such as diabetes, stroke and cardiovascular disease have emerged to outpace to infectious disease in some cases;
4. Biomass burning and dust pollutes many thousands of square kilometers and exposes tens of millions of people of short periods of time (days);
5. Megacities in Africa have exploded with too many cars and pollution levels are likely to be high;
6. The wet season, which is similar to the winter season in the United States is likely to lead to influenza which may increases susceptibility to serious health outcomes from COVID-19;
7. Vector-borne and water-borne diseases will arrive with the wet season with has begun in countries like Nigeria and will begin starting in July further north in Sahelian countries;
8. Many governments have allowed businesses, schools and universities to open;
9. There is no vaccine.
I am going to focus on what we know about the changes in COVID cases and the Environment (my zone).
How Seasons in Africa Work
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Rainfall patterns in Africa (mm/month for winter, spring, summer and Autumn ) |
The rainfall in Africa (25N-25S) tends to follow the overhead Sun leading to the following pattern if you are in
West Africa and North of the Equator:
Wet Seasons (May-October), Dry Season-fire (November-April) in West Africa
If your location is in Nigeria, Ghana, Togo, Benin, you are likely to get rain in March which moves north with a short drier period in August followed by a second wet period. If you live further north in Senegal, Mali, Niger you get one rainy starting in July and ending in late September. The entire region will become dry by December in general. During the dry season, there is the Harmattan with dust from the Sahara desert and lots of fires linked biomass burning.
If you lived
south of the Equator in Southern Africa
Wet Seasons (November-April)
Dry Season-fire (May-October), in Southern Africa
If your life in the Republic of Congo, Angola, and Zambia the rainy period begins in November through April. The rainfall patterns in the Southern Hemisphere are varied and as one goes further eastward the pattern becomes more complex. Beginning in May we see large scale fires in Southern Africa linked to biomass burning.
Examples of current COVID Cases in South Africa, West and Southern Africa
South Africa (approximately 60000 cases)
In the next 10 days, the winter season will begin in South Africa. The autumn season has seen a steady rise in COVID cases and the situation is likely to get worse as people are more likely to spend more time indoors because of colder temperatures and rainy conditions especially in Cape Town. While you can recover from COVID, other confounding factors from the flu and poor air quality are likely to increase the risk of dying. The number of reported daily positive cases in South Africa have increased from 698 cases on May 12 to 3359 cases on June 12. The number of recorded deaths increased from 12 on May 11 and 70 as of June 12.
The Democratic Republic of Congo (DRC) -(4600) and Angola (160)
The DRC and Angola are near each other but have very different COVID-19 reported loading. Angola took early pre-emptive action to limit COVID-19 by closing borders and limiting international flights.
https://www.namibian.com.na/199267/archive-read/Angola-closes-borders-for-15-days
This may have helped reduce the numbers of its COVID-19 cases to a current value of 130 positive cases. However, according to Worldometer, they have only conducted about 10000 tests.
The neighboring DRC on the other hand has an estimated 4700 cases with more than 100 new cases reported per day over the last month. Both the DRC and Angola are in the dry season with many active fires
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June 12 Satellite estimated Fire in Southern Africa |
Because of the fires, we expect that poor air quality is occurring and will continue over the next 3 months. This is a red flag for those with respiratory or cardiovascular disease to be very careful and to keep face covered if poor air quality is detected.
West Africa
Similar to Southern Africa, COVID-19 cases have risen since April. We examine Ghana, Nigeria and Senegal, which have all opened their economies and governments to some degree. Senegal never really completely shut down but had a night curfew. Nigeria, Ghana and Senegal all have megacities that are growing and could possibly become epicenters like many cities in the United States. Nigeria is West Africa's most populated nation with nearly 200 million inhabitants. Senegal and Ghana are considerably smaller.
Nigeria (approximately 15000 cases).
Has seen a steady increase in the numbers of COVID cases with more than 15,000 total cases and a steady increase in daily positive cases.
Ghana (approximately 11000 cases) -has more than 11 thousand cases with an earlier peak in early May and a steady number of cases since June.
Senegal (approximately 5000 cases) - has approximately 5,000 positive cases since March with a steady increase of more than 100 cases since early June.
Potential Environmental Impacts for West Africa
The wet season began along the Gulf of Guinea countries such as Nigeria and Ghana in mid-to-late March. Last night there was rain in Senegal --which is a little early.
With the wet season comes a set of vector-borne and water-borne diseases along with influenza. In fact, the wet season tends to be the coolest (not very cold) but rain can limit activity and keep more people in the house. Possible diseases once the rain began to fall (now through October)
- malaria
- yellow fever and Dengue
- influenza
-acute respiratory infection
Influenza and acute respiratory infection (pneumonia) like mid-latitude countries occur during the coolest and wettest part of the year in West Africa. A paper lead my colleague Dr. Toure from Senegal shows that the largest numbers of reported cases for adults and children during wet season under normal conditions during 2015-2016.
Influenza, acute respiratory infection, and vector/water-borne diseases could pose a serious threat to patients that come down with COVID-19.
The rainy season and the associated diseases could:
- Increase transmission because of indoor activity with the wet season;
- Increased susceptibility by weakening immune systems if one is fighting off another disease;
- Produce a much higher burden on hospitals as they cope with COVID-19 patients;
- Make it difficult for people with influenza or acute respiratory disease to distinguish it from COVID-19.
After one or two months of dry weather, West Africa countries will have to deal with the burden of dust and biomass burning and Southern Africa will have to contend with the wet season. Because the cases of COVID-19 were relatively small during the last dry season in West Africa and wet season in Southern Africa any prediction of what may be expected is highly uncertain.
Key things to remember for the African Continent over the next year:
1. The virus is in full effect around the World;
2. Mask, social distancing and hand washing should be followed no matter what the case;
3. The capacity of the public health care system must be monitored very carefully as the increase in cases in locations such as India, Brazil and now South Africa shows that the number of cases can increase quickly;
4. The situation will remain dangerous until a vaccine is available (2021-2022).
COVID-19 and the Caribbean and SE US
Poor air quality from the Saharan Air Layer (SAL) has already been detected in Senegal and Cabo Verde (see figure). Over the next 2 months, millions of tons of dust will be transported across the Atlantic degrading air quality. This will make people with respiratory, cerebrovascular, and cardiovascular diseases more susceptible to poor outcomes from COVID-19. In addition, the Caribbean will have to prepare for rain associated with easterly waves and potentially tropical cyclones.
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Dust leaving the African Coast on June 12, 2020 |
The number of hurricanes is projected to be higher than normal, but let us hope that their impact is limited and not capable of becoming major storms like Hurricane Dorian.
https://cimss.ssec.wisc.edu/satellite-blog/wp-content/uploads/2019/09/190901_190902_goes16_infrared_Dorian_anim.gif