America’s CDC report on Zika infection: Lessons for Tanzania


IN June 8, 2017, the Centers for Disease Control and Prevention (CDC) published an article in the Morbidity and Mortality Weekly Report indicating that 1 in 20 US pregnant women with Zika infection have babies with birth defects.

In this article, I’m trying to highlight some of the observations which may seem to be interesting to our readers.

Although we don’t have the Zika virus in Tanzania, the CDC report alluded above is cautioning the public, at large, to be more vigilant in sustaining control efforts towards mosquitoes, in particular, with regard to Aedes aegypti mosquitoes which have been associated with Zika infection.


Because our people often travel to the US, Brazil, and other Latin America countries, they may unknowingly, visit areas which have been reported to have the Zika virus. If they travel to areas with Zika, they should seriously consider whether they want to conceive a pregnancy after visiting such areas.

The CDC report reviewed a total of 2,500 pregnant women with possible Zika infection and observed birth defects which are puzzling. We can’t easily explain why and how most of the babies developed birth defects or abnormalities.

Similarly, the authors can’t explain why children developed abnormal development (milestones) several months after birth. In the next section I’ll describe some of the findings to share the puzzle with our readers.

Of the 2,500 women with possible Zika infection, only 60 percent (1,500) were confirmed to have Zika; the remaining (40 percent) 1,000 the infection was unconfirmed.

Although earlier reports showed an association between Zika with microcephaly (small head), the current report has many more findings which some scientists say they are interesting and idiopathic.

The report linked the birth defects with gestation age at which women contracted the Zika infection. Those women who were infected earlier either in first, or second trimester of pregnancy compared with third trimester had a larger proportion of babies with birth defects, eight percent, five and four percent, respectively.

If a woman contracted Zika in the third trimester of pregnancy one wouldn’t expect a baby to have a defect because neural development would have been completed by then but in this report the authors observed things which we say are interesting.

Observations of birth defects hadn’t been reported in earlier reports. Other surprises were that although some babies were born with a normal head size (in Tanzania the average being around 33cm), some babies were found to have some underlying brain abnormalities.

They also experienced slow head growth and developed microcephaly afveloped microcephaly afveloped microcephaly af ter birth. Although some babies didn’t have a small head at birth, some of them developed problems with vision and hearing problems later in life.

We aren’t sure if the babies will also develop abnormalities with the remaining 12 cranial nerves later as they grow older. I remember when we were being taught the nervous system the aspect that dealt with the cranial nerves in our third year lectures at the medical school, the late Professor William Makene, Dean of the Faculty of Medicine in 1973, taught us ways to remember how to test the 12 nerves and see if a patient had abnormal findings.

He told us we should be able to communicate with the patient. He taught us a simple way to remember the first cranial nerve and the others. He taught us how to test the first cranial nerve called the Olfactory nerve by asking the patient to smell some perfume.

The fourth nerve which is the Vagus nerve dealing with voice and breathing while the seventh is the facial nerve which you can test by asking the patient to whistle or tightly close the eyes as you try to open them.

These days when you walk around you see some people with clinical features of stroke on the face because they show the angle of the mouth pulled on to one side. That means they have a Belsy Palsy or paralysis of the facial nerve.

Such people can’t whistle because the seventh nerve is affected. Nevertheless, keeping in mind the birth defects associated with Zika, we shouldn’t be surprised if we see the next CDC reports pointing out other abnormalities associated with the cranial nerves.

Already CDC has reported crying and breathing problems. Because we know the Vagus nerves supplies the diaphragm from below as if one has opened an umbrella and looked at the metallic sticks from the inside, problems of breathlessness have been described with Zika infection.

As regards Tanzania, we should continue being vigilant in our efforts to control mosquitoes. We know Aedes mosquito prefer to breed in water found on axils of trees such as those seen branches of coconuts.

We also know the Government is making efforts to spray larvicides to kill larva. In addition, it is encouraging in-door and out-door spraying to kill other mosquitoes. It is also distributing treated nets and educating people to build houses which have wire mesh to keep mosquitoes from getting inside people’s houses.

When I was young I used to see mosquitoes biting children who were left sleeping outside their house during the day but lucky enough we haven’t had the Zika virus in Tanzania.

Both adults and children should cover themselves with long sleeve shirts and trousers so that they do not get bitten by mosquitoes throughout the day. If possible they should apply mosquito repellents.

We should also thank the Almighty God because we have been very lucky so far. If you read the history of Zika infection you will notice that the virus had been described in some areas of Uganda in 1947 and Tanzania is its neighbour.

Let us also pray that things continue to be as passive or else we would have been in trouble.

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