Ebola in pregnancy

What is Ebola?

The Ebola virus is a single-stranded, unsegmented, enveloped RNA virus with a characteristic filamentous structure (Figure 1) belonging to a family called Filoviridae. To date, two members of this virus family have been identified; the Marburg virus and the Ebola virus, and five different species of the Ebola virus have been isolated (Taï Forest, Sudan, Zaire, Reston and Bundibugyo) (Centers for Disease Control and Prevention (CDC), 2014). Filoviruses are transmitted to humans from animals—both the Ebola and Marburg virus have been isolated in fruit bats (Albarino et al 2013). However, once a human is infected, the virus can spread from person–to-person.

The Ebola virus was first identified in 1976 in Northern Zaire (now Democratic Republic of Congo). There were 318 reported cases with 280 deaths (WHO, 1978) (Table 1).

The virus was named after the Ebola river in northwest Zaire, where the first case was found in the village of Yambuku at the Yambuku Catholic Mission Hospital. At the time of the outbreak, the hospital had 120 beds and 17 medical staff including three Belgian nuns who were qualified midwives. Each day five syringes and needles, that were rinsed in warm water between uses, were issued to health care workers for use in the hospital's antenatal clinic, outpatient clinic and inpatient wards.

Origin of Ebola

The first known case of Ebola virus disease (EVD), previously Ebola haemorrhagic fever (EFH), was reported in a 44-year-old man who worked in the mission school in Yambuku. He had bought and ate fresh smoked antelope and monkey meat on the 22 August. Four days later, he attended the Mission Hospital presenting with malaria-type symptoms. On arrival at the hospital, due to his malarial symptoms, he was treated for malaria and given an injection of chloroquine. Following this, his symptoms resolved and he was apyrexial until 1 September when he developed a temperature and other symptoms now associated with EVD; including gastrointestinal bleeding. He died a week later, on the 8 September 1976. A further nine cases occurred during the first week of September. All of the individuals had received treatment for other diseases at the outpatient clinic of the Mission Hospital. The hospital was closed on the 3 October; 13 of the 17 members of staff at the hospital acquired the disease.

The current West African outbreak is the largest since the Ebola virus was first discovered in 1976. There have been more cases and deaths in this outbreak than all other cases combined. It has spread between countries starting in Guinea then spreading across land borders to Sierra Leone and Liberia, by air (1 traveller only) to Nigeria, and by land (1 traveller) to Senegal and Mali. Spain and the US have also experienced travel-associated cases of Ebola, as well as localised transmission. However, Nigeria was declared Ebola free by the WHO on 20 October after being free of the disease for 42 days (WHO, 2014a).

Transmission

The Ebola virus causes an acute, serious illness which is often fatal if untreated. Pregnant women are known to have increased mortality rates compared to non-pregnant women (Mupapa et al, 1999). The mode of acquiring natural infection with the Ebola virus is unknown. Ebola is transmitted to humans through close contact with blood, secretions, or other bodily fluids of animals infected with the virus such as chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines. Secondary person-to-person transmission results from close personal contact with an infected individual through broken skin or mucous membranes—such as eyes, nose, mouth or vagina—or with blood, secretions, or other bodily fluids of infected people; this includes urine, saliva, sweat, faeces, vomit, blood and semen. It also includes contact with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids. This places health professionals at an increased risk of contracting the virus when providing care for patients with Ebola. However, if full infection control procedures are strictly followed, health professionals or those who come into contact with patients are not at risk. The Ebola virus is not transmitted through water or air. There is also no evidence that it is spread by mosquitos or other insects.

It is suggested that burial ceremonies in which mourners have direct contact with the body of the deceased person can also play a role in the transmission of Ebola (WHO, 2014b).

Once an individual recovers from Ebola, they are no longer infectious. However, the Ebola virus has been reported in semen for between 7 and 12 weeks (WHO, 2014b; CDC, 2014). Therefore, it is advised to refrain from sex (including oral or anal sex). Where this is not possible condoms should be worn.

Incubation

The illness-to-infection ratio for the Ebola virus is unknown and it is suggested that mild or asymptomatic infections can occur (CDC, 2014). However, there is no evidence of how common this is and why some individuals may be more susceptible than others. The incubation period ranges from 2 to 21 days; the average is approximately 1 week. In cases resulting from a needle stick injury (WHO, 2014b), the incubation period is 6 days. Humans are not infectious until they develop symptoms of the disease.

The onset of the illness is sudden, and initial symptoms resemble those of influenza: fever, headache, general malaise, myalgia, joint pain, and sore throat are commonly followed by vomiting, diarrhoea and abdominal pain. A transient measles-like skin rash often appears at the end of the first week of illness. Other physical findings include pharyngitis, conjunctivitis, and jaundice. After the third day of illness, haemorrhagic manifestations are common and include petechiae (bleeding into the skin) as well as bleeding, which can be internal and external and seen in urine, stools and gums. Laboratory findings include low white blood cell and platelet counts with elevated liver enzymes. People who recover from an Ebola infection develop antibodies that last for approximately 10 years. It is unknown whether they can become infected with a different strain of EVD. Some individuals who have recovered have developed long-term joint and vision problems (CDC, 2014).

Diagnosis

Confirmation of the disease is made through specific investigations. It can be difficult to distinguish EVD from other infectious diseases such as malaria, typhoid fever and meningitis. Table 2 shows the laboratory tests that can be used to confirm Ebola virus.

Treatment and vaccines

There is as yet no proven treatment available for EVD. However, a range of potential treatments including blood products, immune therapies and drug therapies are currently being evaluated. No licensed vaccines are available yet, but two potential vaccines are undergoing human safety testing (WHO, 2014b). Treatment is currently supportive and involves rehydration with oral or intravenous fluids.

Pregnancy

In the 1976 outbreak of Ebola, of the 105 women admitted to hospital with EVD, 15 (14%) were pregnant (Mupapa et al, 1999). Of these, 4 (27%) women were in the first trimester, 6 (40%) in the second trimester and 5 (33%) in the third trimester. All of the women presented with signs of haemorrhage and severe genital bleeding. Table 3 shows the signs and symptoms in found in women with EVD.

It is suggested that pregnant women with EVD present with clinically more severe symptoms and complications when compared to non-pregnant patients with EVD (Mupapa et al, 1999). This is similar to other infectious disease such as malaria, tuberculosis and Lassa fever, which are reported to be more severe in pregnant compared to non-pregnant women (Brabin, 1985; Foster, 1996).

Spontaneous abortion is also increased in EVD and other haemorrhagic infections such as Lassa fever (Price et al, 1988). There were no reported differences in the clinical course of the infection related to parity or age of the woman. Only one woman survived, and all other women died within 10 days. The surviving woman was 32 years old and had a curettage following an incomplete abortion.

Only one of the women gave birth to a live full-term baby. The mother developed a fever 4 days prior to delivery and the baby developed a fever and died 3 days later.

There is no recorded evidence of babies born to mothers who have EVD surviving. In the outbreak at the Mission Hospital in Yambuku it was reported that 11 live babies were born to Ebola-infected mothers. Sadly all 11 babies died within 19 days (WHO, 1978). The cause of death is not clear, but it is likely that they died as a result of neonatal EVD. However, no virological or pathological data were recorded; therefore, death could have been the result of a neonatal infection unrelated to Ebola or one of the several other causes which contribute to the high neonatal mortality rates. Seven of the ten babies were reported to have a fever. The route of infection from mother to baby is not clear; although it is likely that transmission will occur during birth, or through breast milk.

It is recommended that infants who are born to mothers with EVD avoid direct close contact with their babies. However, this is only if their babies can receive adequate care and nutrition from other sources. Transmission can occur through close contact with the mother and this is likely to happen during labour. While the virus has been isolated in breast milk, it is still not clear if the disease can be transmitted by this route. Advice should be similar to the prevention of HIV transmission in resource-limited settings; the risk of transmission must be balanced against the risk of malnutrition and other infections. If there is a safe alternative for the infant then breastfeeding is not advisable.

It is essential that all health care workers proceed with the utmost caution and that barrier nursing techniques are used. At the time of writing, 450 health care workers have developed Ebola and of these 244 have died (WHO, 2014b).

Over a decade ago, Peters and LeDuc (1999) stated that for the future, a pre-planned response team will be required: one which can perform selective functions and equipped to deal with an outbreak. This is a thought for the future as we cannot underestimate how communities are being affected, including the mental strain of living in an epidemic. WHO have recognised this mental anguish and published a guide called ‘Psychological first aid during Ebola virus disease outbreaks’ (WHO, 2014c).