Abstract
Chikungunya is a vector-borne infection which is caused by the chikungunya virus.
It is transmitted to humans by infected female mosquitoes (Aedes aegypti and Aedes albopictus also called tiger mosquito) which breed in stagnant water and are also responsible for dengue fever.
These mosquitoes bite only during the daytime, and the peak activity is in the early morning and late afternoon.
The first chikungunya outbreak occurred in southern Tanzania in 1952. The disease is caused by a ribonucleic acid (RNA) virus that belongs to the Alphavirus genus of the family Togaviridae. The virus’s name comes from the Makonde language of Tanzania and means to bend up. It describes the stooped appearance of sufferers with joint pain.
Chikungunya has clinical features similar to those of dengue and Zika and can be misdiagnosed in areas where they are common.
Introduction
Chikungunya is a vector-borne infection which is caused by the chikungunya virus.
It is transmitted to humans by infected female mosquitoes (Aedes aegypti and Aedes albopictus also called tiger mosquito) which breed in stagnant water and are also responsible for dengue fever.1
These mosquitoes bite only during the daytime, and the peak activity is in the early morning and late afternoon.
The first chikungunya outbreak occurred in southern Tanzania in 1952. The disease is caused by a ribonucleic acid (RNA) virus that belongs to the Alphavirus genus of the family Togaviridae. The virus’s name comes from the Makonde language of Tanzania and means to bend up. It describes the stooped appearance of sufferers with joint pain.
Chikungunya has clinical features similar to those of dengue and Zika and can be misdiagnosed in areas where they are common.
Prevalence
Chikungunya is prevalent mostly in Africa, Asia and the Indian subcontinent. The virus has led to major epidemics in Asia and Africa since 2004. In 2013 it appeared as an emerging infection in America. An outbreak in 2015 affected several countries around America.2
Symptoms
2. Joint pain which is often debilitating and can last for variable duration from a few days to weeks, several months or even years
3. Gastrointestinal symptoms, abdominal pain, may also occur
Most of these symptoms are very general, therefore the clinician should be vigilant, especially if symptoms persist for more than a few days.3
Signs and Symptoms in Infected Pregnant Women
1. Joint and muscle pains: joint pains are often so severe as to make the patient bend over and be unable to walk properly. The ankle, elbow joints and wrists are particularly affected, and the pain is excruciating, especially in the morning. The pain might persist for a week or for more than a month, and at times there might be swelling around the joints.4
2. Fever: high and recurring fever as high as 40°C.
3. Chills: as with malaria, chikungunya infection causes chills.
4. Rash: which is maculopapular occurs in 40–50 per cent of cases, two to five days after onset of symptoms.
5. Headaches: severe headaches accompany chikungunya infection and can be very painful.
6. Pain in the lower back region: along with a headache, the lower back may also ache.
7. Nausea, vomiting and diarrhoea: the feeling of having an upset stomach with the sensation of throwing up, followed by vomiting, is symptomatic.
8. Fatigue: a feeling of tiredness and being low on strength.
The disease can be acute or chronic.5
Acute Phase
In the acute phase, there are two stages:
1. A viral stage, during which viraemia occurs during the first five to seven days
2. A convalescent stage in which symptoms improve and the virus cannot be detected in the blood, lasting approximately 10 days
Chronic Phase
The chronic phase of the infection has been poorly described in the obstetric population. Serious complications are uncommon. Mostly infection is mild and may go unrecognised or be misdiagnosed as dengue in areas affected by dengue.
Incubation period is usually between 3 and 7 days but can vary from 1 to 12 days.
Chikungunya is not fatal, but the symptoms can be severe and cause debilitating and long-lasting joint pain.6
Effects of Chikungunya Infection on Maternal and Neonatal Outcomes
The effects of chikungunya infection on maternal outcomes are limited.
There is no clear evidence that pregnant women infected with chikungunya have more obstetric complications.
Chikungunya virus is not transmitted to the fetus. However, immunity is transferred to the fetus that may last a few years after the birth.7
Vertical Transmission
If the woman becomes infected just before delivery, the virus is vertically transmitted to the fetus during labour.8 The risk for vertical transmission is increased to 50 per cent when maternal viraemia is present during delivery.6 In such cases, the neonate can be severely infected during the birth.
The largest study from Latin America at four large regional maternity hospitals in three different centres involving 169 symptomatic newborns suggested that vertical transmission during labour and delivery ranged between almost 27 per cent and 48 per cent and mortality rate was 5 per cent.8
Neonatal Implications
Infected neonates should be treated at a tertiary hospital immediately, as they are at a higher risk of developing morbidities and mortalities. When maternal infection occurs late in pregnancy, serious and life-threatening fetal and neonatal complications can occur such as meningoencephalitis and disseminated intravascular coagulation.9
Caesarean section does not prevent transmission.10
The death rate is not high, but mortality has been observed in large chikungunya outbreaks.11
The most common clinical signs in newborns were fever, irritability, rash, seizures, diffuse limb oedema, meningoencephalitis and bullous dermatitis.
Pregnant women with chikungunya should be treated in highly specialised obstetric and neonatal units to prevent adverse outcomes. Once infected, lifelong immunity develops against the disease.11
Congenital infection rate is unrelated to mode of delivery.
The predominant clinical manifestations in symptomatic newborns are fever (100%), irritability (90%), rash (84%), generalised oedema (86%), hyper-algesia (94%), stiff neck or pain on mobilisation (38%) and hemodynamic instability (52%).12
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