When Is a Baby in Danger of Zika Virous

Br J Gen Pract. 2022 Mar; 66(644): 122–123.

Zika virus infection during pregnancy: what, where, and why?

Pranav Pandya, Manager and Clinical Lead of Fetal Medicine

Academy College London Hospitals, London.

Eleni Nastouli

Clinical Atomic number 82 in Virology, Academy College London Hospitals, London.

Philip Gothard

Consultant Dr., Infirmary for Tropical Diseases, London.

On 1 Feb 2022 the Globe Wellness Organization declared a Public Health Emergency of International Business organization following reports of large clusters of microcephaly and Guillain-Barré Syndrome associated with an increase in cases of Zika virus (ZIKV) infection in French Polynesia (2014) and Brazil (2015– 2016).¹ The Committee emphasised that there was '... no public health justification for restrictions on travel or trade' and the primary interventions were to control mosquito populations and prevent bites in pregnant women. Why has this happened and how might it affect patients attending primary care in the United kingdom of great britain and northern ireland?

ZIKV was get-go isolated from a Rhesus monkey in Republic of uganda in 1947.² The following year information technology was identified in Aedes mosquitoes, which differ from malaria-transmitting Anopheles mosquitoes past biting during the mean solar day. ZIKV has been found throughout Africa and South Eastern asia where infection is asymptomatic or produces a mild febrile disease and rash which goes undiagnosed. The starting time outbreak was not recorded until 2007 when iii-quarters of the population of Yap Island in Federated states of micronesia became infected.³

The current epidemic of ZIKV infection began in early 2022 in northeastern Brazil. Since then ZIKV transmission has been confirmed in 35 countries.⁴ Ane theory is that ZIKV was carried to Brazil past infected Pacific Islanders visiting an international canoeing upshot in Rio de Janeiro in August 2014. In September 2022 clinicians working in Pernambuco state noticed an increase in newborn babies with microcephaly. The Ministry of Wellness rapidly established a register and within 3 months recorded 4180 suspected cases, including 68 deaths, compared to a total of 147 reports in the whole of 2014.⁵ A review of the first 35 cases noted that 74% of mothers reported a rash during pregnancy and 71% of infants had severe microcephaly.⁶ ZIKV RNA was detected in the amniotic fluid of ii mothers and from the brain of a baby who died presently after birth.⁷ Taken together these information bespeak a strong clan betwixt ZIKV infection during pregnancy and microcephaly, although a causal relationship is yet to be proven.

ZIKV infection has an incubation period of 3–12 days. Patients may present with a fever, rash, arthralgia, and conjunctivitis. The illness is self-limiting and lasts for up to a week. Astringent cases are uncommon. Information technology tin be difficult to distinguish ZIKV infection from other viral illnesses such as dengue and chikungunya, which are also transmitted by Aedes mosquitoes. Population seroprevalence studies from the outbreak in Micronesia showed that 80% of ZIKV infections were asymptomatic,⁸ which presents a diagnostic problem in pregnancy if ZIKV crosses the placenta.

PRACTICAL ADVICE

Public Health England (PHE) and the Royal College of Obstetrics and Gynaecology released joint interim guidelines on 29 January 2016^ix followed by PHE and the Imperial Higher of General Practitioners with principal intendance guidelines on four February 2016.¹⁰ They recommend that pregnant women who nowadays with symptoms consistent with ZIKV infection within ii weeks of travel to an expanse of agile transmission (Figure 1) should be tested for ZIKV.

Figure ane.

There is a wide differential diagnosis of illnesses in returning travellers, including malaria, and patients with symptoms should be discussed with a doctor experienced in their cess. EDTA plasma and urine samples from symptomatic patients should be sent to the Rare and Imported Pathogens Laboratory at Porton Down (Box i). Testing involves opposite transcription polymerase chain reaction (RT-PCR) of blood and urine. Antibody testing is not yet available in the Great britain and is currently less reliable due to potential cross-reaction with similar viruses, such as dengue and yellow fever. This may change presently and for now PHE recommend that all patients suspected of ZIKV infection, and any meaning women exposed to ZIKV, should have a serum sample collected and saved. While these interim guidelines are welcome, information technology is important to exist aware that there are express data available to brand conclusive recommendations. Pre-exam counselling is important, particularly every bit the full characteristics of the tests are unknown and false-negative results are possible.

All pregnant women who have potentially been exposed to ZIKV should be referred to their local maternity unit for four-weekly fetal ultrasound scan (USS) examinations. This includes asymptomatic patients, those who have had symptoms outside the testing window and patients who take tested negative for ZIKV by RT-PCR. Microcephaly is a caput circumference below the 2.fifth centile for gestational age and standard fetal USS is a sensitive screening test for this and other intracranial abnormalities such as ventriculomegaly and calcification.

Pregnant women with a positive ZIKV RT-PCR or with concerning findings on USS should be referred to a fetal medicine service for evaluation and follow upwards. This may involve a detailed USS and possibly amniocentesis from 15 weeks to exam for ZIKV and other causes of neonatal infection in the amniotic fluid. Fetal encephalon MRI may detect abnormalities non seen on USS. Information technology is important to retrieve that microcephaly and other intracranial anomalies may be caused by a number of disorders unrelated to ZIKV. PHE has clear guidelines for evaluating significant women with a rash, in particular, advice on when to test for rubella, varicella, or parvovirus B19.^eleven

Significant women should consider fugitive travel to areas with ongoing ZIKV outbreaks and seek communication from a travel wellness specialist. The first trimester probably carries the greatest risk of microcephaly. If travel is unavoidable they should exist advised to have great care to protect against daytime mosquito bites past covering up and using insect repellents.

In that location is emerging evidence of ZIKV manual through sexual intercourse.¹² Information technology is not known how long ZIKV persists in semen and UK and Usa guidance differs, however this is unlikely to exist a common route of transmission. For simplicity our advice is to follow the U.s.a. Centers for Affliction Control and Prevention guidance to abstain from sexual practice or use condoms for the duration of the pregnancy if a male partner has been in a Zika virus area.⁹

ZIKV poses significant challenges in the counselling process in pregnancy as limited bear witness exists to almost the proportion of infected patients who are asymptomatic and have brief, low level viraemia, the chance to the fetus relative to the fourth dimension of infection, the reliability and significance of laboratory tests, and the likelihood of the child developing neurological sequalae. These questions are the field of study of ongoing research, only in the meantime, ane.iv million UK travellers visit countries with ongoing ZIKV transmission each year and of these nosotros estimate that around 280 000 are women of child-bearing age. If merely a small number of these are significant that represents several 1000 women who may consider themselves at risk. Fortunately the limited information suggest that the risks to the infant are very low. However pregnancy is often an anxious time and GPs tin can help expectant mothers by being aware of the latest guidelines and where to seek assist.

Notes

Provenance

Freely submitted; non externally peer reviewed.

REFERENCES

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Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4758474/

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