Biology Reference
In-Depth Information
11.2.5. Multiorgan dysfunction and shock
The extent to which multiorgan dysfunction and shock are attributable to
sepsis-like inflammatory responses to
P. vivax
, the gram-negative bacterial
co-infection known to occur during
P. vivax
infection (
Piyaphanee et al.,
2007
;
Sur et al., 2006
), or both, requires further study. Negative blood cul-
tures reported in some series are limited by widespread pre-hospitalisation
use of antibiotics in the community, and the known insensitivity of pre-
antibiotic blood cultures in bacterial sepsis (
Davis et al., 2011
), with con-
comitant sepsis not being excluded by negative blood cultures.
Nevertheless, plausible hypotheses have been advanced to explain septic
shock-like presentations in
P. vivax
infections, particularly in endemic set-
tings with a high prevalence of bacterial co-infections, including
Plasmo-
dium
-induced priming of host inflammatory responses to bacterial TLR
agonists (
Franklin et al., 2009
;
Leoratti et al., 2012
) (Section
11.1.6
).
11.2.6. Pregnancy-associated malaria and low birth weight
P. vivax
does not appear to sequester in the placenta although published
reports are limited (
McGready et al., 2004
). Placental histopathology shows
haemozoin deposition, but inflammatory and pathological changes are
otherwise modest (
McGready et al., 2004
). Systemic and placental inflam-
matory responses and microvascular dysfunction from vivax malaria may
cause deleterious utero-placental haemodynamic effects and foetal growth
restriction (
McGready et al., 2004
;
Rogerson et al., 2007
;
Umbers et al.,
2011
;
Rijken et al., 2012b
). Maternal anaemia, common in vivax malaria
(
Poespoprodjo et al., 2008
;
Rijken et al., 2012a
), is likely to be an additive
cause of low birth weight (
Rogerson et al., 2007
).
12. CONCLUSION
It is clear that
P. vivax
is responsible for major morbidity and sig-
nificant mortality in vivax-endemic areas. A single infection causing febrile
illness in otherwise healthy individuals rarely progresses to severe disease,
particularly with early treatment and anti-relapse therapy. Nevertheless, it
has been long recognized that
P. vivax
can cause severe illness and fatal out-
come in the presence of acute and chronic co-morbidities. Such co-mor-
bidities, including malnutrition, anaemia, concurrent bacterial infections
and chronic renal, liver and lung disease, are common in vivax-endemic
regions. While some of these co-morbidities are alternative causes of severe
and fatal disease in co-incidentally parasitized patients, others are likely to
