Introduction
The reemergence of brucellosis in Central Asia and the Middle East
(Godfroid, et al., 2005; Seleem, Boyle, & Sriranganathan, 2009; Pappas,
Papadimitriou, Akritidis, Christou & Tsianos, 2013) is a large part
because of its changing epidemiology (Dahouk et al., 2007); the role of
animal husbandry tradition; and a culture of raw milk consumption. These
factors are also major reasons for the continued persistence in many
countries around the world (Zhong et al., 2013; Wallach, 1997).
One health implication of human brucellosis (Brucella melitensis ;
the most common and virulent species of human brucellosis), one of the
most widespread zoonotic diseases in the world, is the potential role in
of the bacteria in inducing fetal loss. The etiology of abortions and
stillbirths are complex and can be attributed to either non-infectious
causes (e.g., congenital anomalies, placental insufficiency, placental
abruption and asphyxia), or to infectious agents (Goldenberg &
Thompson, 2003). Approximately 9 to 15 percent of stillbirths are caused
by infectious diseases and in particular, infections during early in
pregnancy (Gibbs, 2002). Economic factors can influence the role of
infectious diseases and stillbirths. In middle- and low-income countries
50 percent or more of stillbirths can be attributed to infections,
whereas, in high income countries, only 10 to 25 percent of maternal or
fetal infections can account for stillbirths (Goldenberg & Thompson,
2003; Goldenberg, McClure, Saleem & Reddy, 2010). Specific infectious
agents linked to stillbirths include syphilis, malaria, toxoplasmosis,
parvovirus B-19, chorioamnionitis, and Listeria monocytogenes .
Less definitive links to stillbirths include the genital
mycoplasmas, Chlamydia trachomatis , HIV, and group B
streptococci. and others (Gibbs, 2002; Goldenberg & Thompson, 2003).
It has been well documented that animal strains of brucellosis cause
abortions of fetuses and ‘reproductive failure,’ in cows, dogs, goats,
horses, pigs, sheep and even camels. (Lopes, Nicolino, & Haddad, 2010;
Ocholi, Kwaga, Ajogi & Bale, 2005; Samartino, & Enright, 1993)B. Melitensis can be transmitted to humans only from goats
or sheep, through consumption of unpasteurized milk and cheese; through
close contact with animals (i.e. hunting, milking, or caring for sick
[veterinarians]); through meat processing and meat consumption; or
through inhalation or airborne of the pathogen. Rarely, the bacteria can
be transmitted from person-to-person either via sexual contact or
airborne transmission.
The study of the link between human B. melitensis and the
termination of births in humans is a topic that has received a dearth of
attention. Few studies have examined relationship of human stillbirths
and B. melitensis , especially at the cohort or population
level (for exceptions see: Gulsun, Aslan, Satici, & Gul, 2011, and
Rujeni, & Mbanzamihigo, 2014). Others are case reports of stillbirth
and abortions that are limited in scope and sample size (Karcaaltincaba,
Sencan, Kandemir, Guvendag‐Guven, & Yalvac, 2010; Goldenberg et al.,
2010; Mosayebi, Movahedian, Ghayomi, & Kazemi, 2005). These studies,
however, point to the strong possibility that brucellosis is a risk for
adverse health outcome to the human fetus.
In this paper we explore the relationship between human B.
melitensis and stillbirths specifically in the civil population of
Malta during the period 1919 to 1954. The Maltese islands present a rare
opportunity for a population-based inquiry into the potential adverse
effects of brucellosis on fertility through fetal loss. The advantages
of the study site include the following population-based attributes:
First, brucellosis (a.k.a. Malta or Mediterranean Fever) was a
notifiable disease since the early 20th century and it
remained endemic throughout the study period. Second, monthly statistics
of births and stillbirths by sex were published since 1900. Third,
pregnant women were at continuous and at high exposure to brucellosis
because of high fertility rates owing to their adherence to strict
Catholic precepts (Tripp & Sawchuk, 2015; 2017). Finally, throughout
the study period, the health care infra-structure was rudimentary along
with little available pre-natal care for expectant mothers putting the
vast majority of women at risk for fetal loss (Savona Ventura & Grech,
1985; Seers, 1957; Tripp & Sawchuk, 2015).