In adults with previous exposure to heterologous strains and partial
immunity, prodromal symptoms are often absent, with an abrupt onset of
fever with intermittent pattern, and either quotidian or tertian frequency
( Kitchen, 1949b ). Kitchen also observed that the pyrogenic threshold with
heterologous reinfection is often higher, depending on the degree of tol-
erance achieved from the preceding infection; reinfection with a homolo-
gous strain usually evokes no febrile response ( Kitchen, 1949b ). Clinical
features of temperate strains with long incubation periods have been
reported to be no different to short-incubation tropical strains ( Hankey
et al., 1953 ).
In vivax-endemic areas, parasitaemia without fever is common ( Luxem-
burger et al., 1996 ; Gamage-Mendis et al., 1991 ; Karyana et al., 2008 ; Harris
et al., 2010 ), even in areas of low endemicity ( Luxemburger et al., 1996 ).
In co-endemic areas, the pattern of fever (or indeed any other clinical fea-
ture) cannot be used to reliably differentiate Plasmodium species in children
( Luxemburger et al., 1998 ). In Thailand, median duration of fever and pro-
portion with fever >38 °C were similar between vivax malaria (2.1 days;
48%) and falciparum malaria (2.4 days; 60%) ( Luxemburger et al., 1998 ).
3.2. Other Symptoms and Signs
Headache, anorexia, vomiting, myalgias, abdominal pain and diarrhoea
commonly occur during the paroxysm of vivax malaria ( Kitchen, 1949a ,
1949b ). Restlessness and delirium can occur at the time of maximum
temperature ( Kitchen, 1949b ). In primary attack in adults, the spleen is
not usually palpable until the end of the first week of symptoms and rarely
reaches the umbilicus in untreated primary infection ( Kitchen, 1949a ).
Similar symptoms and signs are seen in children. In a series of 151 Karen
children with vivax malaria (mean age of 8 years), prominent symptoms
during acute vivax malaria were headache (87%), cough (42%), muscle
pain (35%), nausea (29%), vomiting (24.5%), abdominal pain (25%) and
diarrhoea (4%) ( Luxemburger et al., 1998 ). In this area of low endemic-
ity, clinical anaemia (5%), a palpable spleen (8%) and palpable liver (3%)
were less frequently seen ( Luxemburger et al., 1998 ). Anaemia is more
frequently seen in infancy, and in prolonged, untreated or recurrent infec-
tions (Section 8.1.1 ). No clinical signs or symptoms reliably differentiate P.
vivax from P. falciparum or either species from non-malarial causes of fever
( Luxemburger et al., 1998 ).
Respiratory symptoms have long been recognized as common in
vivax malaria. World War I and II series describe clinical presentations