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6. Parasitic diseases
Malaria
M alaria is a parasitic infection d ue to protozoa of th e g enus Plasmodium, transm itted to
h um ans by th e bite of Anopheles m osquitoes. T ransm ission by transfusion of parasite
infected blood and transplacental transm ission are also possible.
M ost infections are d ue to four species: P. falciparum, P. vivax, P. ovale and P. malariae. A ll
species m ay cause uncom plicated m alaria; sev ere m alaria (d efined by th e presence of
com plications) is alm ost alw ays d ue to P. falciparum.
C linical suspicion of m alaria sh ould be confirm ed w h enev er possib le b y a
parasitolog ical d iag nosis. H ow ev er, treatm ent of suspected m alaria sh ould not be
d elayed w h en confirm atory testing is not av ailable: uncom plicated m alaria can
prog ress rapid ly to sev ere m alaria, and sev ere m alaria m ay cause d eath w ith in a few
h ours if left untreated .
Clinical features
M alaria sh ould alw ays be consid ered in a patient liv ing in or com ing from an end em ic
area, w h o presents w ith fev er (or h istory of fev er in th e prev ious 4 8 h ours).
Uncomplicated malaria 6
F ev er is frequently associated w ith ch ills, sw eating , h ead ach e, m uscular ach e,
m alaise,
anorexia or nausea. I n ch ild ren, fev er m ay be associated w ith abd om inal pain,
d iarrh oea and v om iting . A naem ia is frequent in ch ild ren and preg nant w om en.
Severe malaria
I n ad d ition to th e abov e, th e patient presents w ith one or m ore of th e follow ing
com plications:
– Im paired consciousness, d elirium or com a
– Seizures, g eneralised or focal (e.g . abnorm al eye m ov em ents)
– P rostration (extrem e w eakness; in ch ild ren: inability to sit or d rink/ suck)
– R espiratory d istress: rapid and laboured breath ing or slow , d eep breath ing
– C irculatory collapse (sh ock): cold extrem ities, w eak or absent pulse, slow capillary
refill tim e (> 3 second s), cyanosis
– Jaund ice (ch eck m ucosal surfaces of th e m outh , conjunctiv ae and palm s)
– H aem og lobinuria: d ark red urine
– A bnorm al bleed ing : skin (petech iae), conjunctiv ae, nose, g um s; blood in stools
– A cute renal failure: urine output < 1 2 m l/ kg / d ay in ch ild ren and < 4 0 0 m l/ d ay in
ad ults, d espite ad equate h yd ration
P atients presenting w ith any of th e abov e features or w ith sev ere anaem ia (see
pag e 3 7 )
m ust be h ospitalised im m ed iately.
Laboratory diagnosis
Parasitological diagnosis
– Microscopy
NTohtei:nbalonoddthfilmick sblmoodayfilbme sneegnaabtilve epadrauseitteo dseqteucetsiotrna,tsiopnecoifetshideepnatrifaicsaittiizoend,
quantification and m onitoring of parasitaem ia.
eryth rocytes in periph eral capillaries in sev ere m alaria, as w ell as in placental v essels
in preg nant w om en.
131
Malaria
M alaria is a parasitic infection d ue to protozoa of th e g enus Plasmodium, transm itted to
h um ans by th e bite of Anopheles m osquitoes. T ransm ission by transfusion of parasite
infected blood and transplacental transm ission are also possible.
M ost infections are d ue to four species: P. falciparum, P. vivax, P. ovale and P. malariae. A ll
species m ay cause uncom plicated m alaria; sev ere m alaria (d efined by th e presence of
com plications) is alm ost alw ays d ue to P. falciparum.
C linical suspicion of m alaria sh ould be confirm ed w h enev er possib le b y a
parasitolog ical d iag nosis. H ow ev er, treatm ent of suspected m alaria sh ould not be
d elayed w h en confirm atory testing is not av ailable: uncom plicated m alaria can
prog ress rapid ly to sev ere m alaria, and sev ere m alaria m ay cause d eath w ith in a few
h ours if left untreated .
Clinical features
M alaria sh ould alw ays be consid ered in a patient liv ing in or com ing from an end em ic
area, w h o presents w ith fev er (or h istory of fev er in th e prev ious 4 8 h ours).
Uncomplicated malaria 6
F ev er is frequently associated w ith ch ills, sw eating , h ead ach e, m uscular ach e,
m alaise,
anorexia or nausea. I n ch ild ren, fev er m ay be associated w ith abd om inal pain,
d iarrh oea and v om iting . A naem ia is frequent in ch ild ren and preg nant w om en.
Severe malaria
I n ad d ition to th e abov e, th e patient presents w ith one or m ore of th e follow ing
com plications:
– Im paired consciousness, d elirium or com a
– Seizures, g eneralised or focal (e.g . abnorm al eye m ov em ents)
– P rostration (extrem e w eakness; in ch ild ren: inability to sit or d rink/ suck)
– R espiratory d istress: rapid and laboured breath ing or slow , d eep breath ing
– C irculatory collapse (sh ock): cold extrem ities, w eak or absent pulse, slow capillary
refill tim e (> 3 second s), cyanosis
– Jaund ice (ch eck m ucosal surfaces of th e m outh , conjunctiv ae and palm s)
– H aem og lobinuria: d ark red urine
– A bnorm al bleed ing : skin (petech iae), conjunctiv ae, nose, g um s; blood in stools
– A cute renal failure: urine output < 1 2 m l/ kg / d ay in ch ild ren and < 4 0 0 m l/ d ay in
ad ults, d espite ad equate h yd ration
P atients presenting w ith any of th e abov e features or w ith sev ere anaem ia (see
pag e 3 7 )
m ust be h ospitalised im m ed iately.
Laboratory diagnosis
Parasitological diagnosis
– Microscopy
NTohtei:nbalonoddthfilmick sblmoodayfilbme sneegnaabtilve epadrauseitteo dseqteucetsiotrna,tsiopnecoifetshideepnatrifaicsaittiizoend,
quantification and m onitoring of parasitaem ia.
eryth rocytes in periph eral capillaries in sev ere m alaria, as w ell as in placental v essels
in preg nant w om en.
131
