A SURVEY FOR RUBELLA VIRUS AND ANTIBODIES AMONG PREGNANT WOMEN  

CHAPTER ONE

INTRODUCTION

Background to study

Rubella virus (RV) causes a benign systemic rash illness when it infects humans as a result of acute infection and causes severe birth defects if acute maternal infection occurs during the first trimester of pregnancy (Willey et al., 2011). This virus is a positive-strand RNA virus that replicates in the cytoplasm of the infected cell. Rubella virus is taxonomically unique, being the sole member of the genus Rubivirus of the familyTogaviridae (Brooks et al., 2007). The rubella virus causes “German measles,” also known as “three-day measles”(Bukbuk et al., 2002), this is usually a milder disease than red measles. Infections occur most commonly in children and the resulting natural immunity is most probably lifelong (Matthews et al., 2011). However, in pregnant women the risk of intrauterine transmission is up to 90% if infection occurs in early pregnancy (8-10 weeks gestation). As the viraemia leads to placental infection and spread of the virus, it causes a chronic infection of the foetus leading to the development of congenital rubella syndrome (CRS) (Matthews et al., 2011).Red/Hard measles or just measles is caused by Rubeola virus.

Rubella virus is an important human pathogen that causes an acute and contagious disease known as rubella, little red, 3-day measles, or German measles (Fokunang et al., 2010). Humans are the only reservoir for this virus (Mounerou et al., 2015). The virus has an incubation period of 2–3 weeks. The route of transmission is air-borne in postnatal cases and transplacental during pregnancy (Kolawole et al., 2014). The disease caused by this virus commonly occurs in childhood and is characterized by a maculopapular rash associated with a low-grade fever, lymphadenopathy, and malaise (Al-Rubai et al., 2010). It can also cause joint pains, headache, and conjunctivitis in adults (Lezan, 2015). Transient arthralgia or arthritis may also occur (Heggie and Robbins, 1969). It is also a rare cause of thrombocytopenic purpura and encephalitis (Sherman et al., 1965). However, up to 50% of rubella cases are subclinical (Horstmann et al., 1965).

Rubella infection is considered relatively benign, and in the absence of pregnancy, the infection is usually mild and self-limiting (CDC, 2001). However, during pregnancy, it has a devastating effect on the developing fetus (Adam et al., 2013, Cradock-Watson et al., 1981) and this represents a major health concern worldwide (Mirambo et al., 2015). Currently, there is no specific treatment for the virus (Olajide et al., 2015). However, its burden can be minimized through use of the live attenuated rubella vaccine (Alleman et al., 2016, Demicheli et al., 2012, WHO, 2014). The control of rubella and congenital rubella syndrome (CRS) relies on a high population level of immunity (Gilbert et al., 2017).

The World Health Organization (WHO) proposed the introduction of rubella vaccine in each country in the year 2000 (Robertson et al., 2003) and different efforts are undergoing in different WHO regions (Martínez-Quintana et al., 2015, CDC, 2010, WHO, 2008). As a result, the burden has declined, although mostly in industrialized countries (Adewumi et al., 2014). However, rubella vaccine is still not available in many developing countries (Njeru et al., 2015) and it is not included in their immunization programs (WHO, 2012). Rubella is an under-recognized public health problem (Cutts and Vynnycky, 1999, Mamvura et al., 2015). In Africa, few countries have included rubella vaccine in their national immunization programs and data on the seroprevalence of the virus are very limited (Martínez-Quintana et al., 2015).

Statement of Problem

Although Nigeria has planned to introduce the rubella vaccine (WHO, 2015), it is currently not included in the national immunization program (Getahun et al., 2016). There are only a few reports on rubella in the country (Cutts et al., 2000a, Gebreselassie and Almaz, 1985), with most containing very old information (Gebreselassie and Almaz, 1985, Sandow et al., 1982) or reporting on suspected cases of measles among children (Mitiku et al., 2011, Getahun et al., 2016, Shiferaw et al., 2016). There is only one recently published report on rubella among pregnant women (Tamirat et al., 2017) and one case report on CRS (Mekonnen, 2017) in the country. All of these indicate that there is scarcity of data and that the magnitude of rubella and its consequences is largely unknown. Hence, the aim of this study was to determine rubella virus infections and immune status among pregnant women before the introduction of rubella vaccine in Kaduna State, Nigeria.

Research Objectives

Rubella Virus (RV) causes a mild disease, but maternal infection early in pregnancy often leads to birth defects known as congenital rubella syndrome (CRS). Rubella remains poorly controlled in Africa despite being a vaccine preventable disease. The aim of this study was to determine the survey for rubella virus and antibodies among pregnant women in Kaduna State Nigeria. The study was carried out on pregnant women attending ante-natal clinic in three different senatorial districts in Kaduna State.