[Emerging Infectious Diseases * Volume 3 * Number 3 * July-September 1997]

[Dispatches]

Jail Fever (Epidemic Typhus) Outbreak in Burundi

D. Raoult,* V. Roux,* J.B. Ndihokubwayo, G. Bise, D. Baudon, G. Martet,
and R. Birtles*
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      We recently investigated a suspected outbreak of epidemic
      typhus in a jail in Burundi. We tested sera of nine patients by
      microimmunofluorescence for antibodies to Rickettsia prowazekii
      and Rickettsia typhi. We also amplified and sequenced from lice
      gene portions specific for two R. prowazekii proteins: the gene
      encoding for citrate synthase and the gene encoding for the
      rickettsial outer membrane protein. All patients exhibited
      antibodies specific for R. prowazekii. Specific gene sequences
      were amplified in two lice from one patient. The patients had
      typical clinical manifestations, and two died. Molecular
      techniques provided a convenient and reliable means of
      examining lice and confirming this outbreak. The
      jail-associated outbreak predates an extensive ongoing outbreak
      of louse-borne typhus in central eastern Africa after civil war
      and in refugee camps in Rwanda, Burundi (1), and Zaire.

Typhus group rickettsioses are distributed worldwide. Rickettsial typhus
has two forms: endemic (murine) typhus and epidemic typhus. Endemic typhus
is caused by R. typhi, usually transmitted to humans by the rat flea,
Xenopsylla cheopis; epidemic typhus is caused by R. prowazekii, transmitted
by the body louse, Pediculus humanus humanus (2). In the United States, R.
prowazekii has also been found in a sylvatic cycle involving flying
squirrels and their ectoparasites (3). Typhus group rickettsioses,
especially epidemic typhus, are associated with wars and human disasters.

During World Wars I and II, typhus spread through North Africa, the Pacific
Islands, and Europe, especially in German concentration camps. In North
Africa, the epidemics involved mainly civilian populations. U.S. forces
were protected by the first vaccine applied on a large scale, the Cox-type
vaccine (4). Epidemic typhus began to decline at the end of World War II
when DDT started to be used as an insecticide. Ethiopia, Rwanda, Nigeria,
and Burundi were the main foci of louse-borne typhus in Africa in the
1970s. Ethiopia reported 1,931 cases in 1983 and 4,076 cases in 1984 (5),
with a death rate of 3.8%(6). However, these data were difficult to
interpret because serologic testing was usually performed with inadequate
techniques, and epidemiologic data were unavailable.

Political instability in Eastern European and African countries has
recently caused conflicts in regions where the risk for typhus outbreaks is
very high. In Yugoslavia and Rwanda, older persons who contracted epidemic
typhus as youths can develop recrudescent illness and become the source of
resurgent epidemics if louse infestation becomes prevalent. Recently, an
outbreak of typhus was suspected in a Burundi jail; we diagnosed epidemic
typhus by amplifying and sequencing portions of the citrate synthase and
the rOmpB genes of R. prowazekii in lice.

Patients

In a jail in N'Gozi, Burundi, a local nurse observed patients with abrupt
fevers of up to 40C in association with a body louse outbreak from
December 1995 to January 1996. Typhus was suspected, and chloramphenicol
was given orally or intravenously. Blood specimens were obtained from nine
patients (all young black men), and sera were sent to Marseille for
serologic testing. Two lice per patient were obtained from the clothes of
Patients Four, Five, Seven, Eight, and Nine; clinical information was also
obtained (Table).

Serologic Investigation

Patients' sera were tested by microimmunofluorescence. Vero cellgrown
rickettsia were purified (7) and placed on slides as spots. R. prowazekii
Breinl strain and R. typhi Wilmington strain were used. Both antigens were
placed on either side of the same slide to compare the serum reactivity
with the two antigens. Sera were diluted from 1/32 to 1/4,096.
Immunoglobulin G (IgG) antibodies were detected by gamma chain specific
anti-human Ig (Bio Merieux, Marcy l'Etoile, France), and IgM was detected
after IgG was removed by RF adsorbent (Behring) (7). The diagnostic cutoff
for microimmunofluorescence in diagnosing rickettsiosis is 1/128 for IgG
and 1/64 for IgM (7,8). All nine patients were positive for both antigens;
however, titers were identical for both antigens in Patients Four and
Eight. In the other patients, antibodies were higher for R. prowazekii than
for R. typhi by one-to-five dilution for IgG. IgM antibodies were at the
same level against both antigens in all patients (Table).

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Table. Clinical and serologic data (by microimmunofluorescence) for nine
patients with louse-borne typhus
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   Patient
   number     One     Two    Three  Four    Five    Six    Seven   Eight   Nine
Age (yrs)    28     21      33     20     27      25     28       50     27
Onset date   1/25/961/26/96 1/6/96 1/19/961/20/96 1/19/9612/16/95 1/13/961/20/96
Peak fever
(C)         40     39.7    40     39.5   40      39.5   39.7     39     40
Neurologic
signs        no     no      yes    yes    yes     yes    yes      yes    yes
   mental
confusion    -      -       yes    no     yes     yes    yes      yes    yes
   seizures  -      -       no     yes    no      no     no       no     no
   coma      -      -       yes    no     no      no     yes      yes    no
Rash         yes    no      yes    no     no      no     no       no     no
   purpuric  no     -       yes    -      -       -      -        -      -
Pulmonary
signs        yes    no      no     yes    yes     yes    yes      no     no
   cough     yes    -       -      yes    yes     no     no       -      -
   dyspnea   yes    -       -      no     no      yes    yes      -      -
Vomiting     yes    no      yes    yes    no      yes    yes      no     no
Splenomegaly no     yes     yes    no     no      no     yes      no     no
Hypotension  yes    no      no     no     yes     no     yes      no     yes
Death        no     no      no     no     no      no     yes      no     yes
Anti-R.
prowazekii   256    1024    2048   256    256     512    4096     1024   256
IgG titer
Anti-R.
prowazekii   256    512     512    256    512     512 7  256      1024   512
IgM titer
Anti-R.
typhi IgG    64     512     128    256    64      0      1024     1024   64
titer
Anti-R.
typhi IgM    256    512     512    256    512     512    256      1024   512
titer
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Polymerase Chain Reaction (PCR) Detection in Lice

Lice were sent to Marseille and arrived dry; they were crushed, and DNA
suitable for use as a template in PCR was extracted using QIAGEN columns
(QIAamp Tissue Kit, QIAGEN, Hilden, Germany). Citrate synthase PCR
amplification incorporated primers 120-M59 (CCGCAGGGTTGGTAACTGC) (9) and
120-508 (CCAAGTGATAAGAGGAGCTT) selected from the R. prowazekii ompB
sequence (10). The citrate synthase amplicons were subjected to restriction
fragment length polymorphism analysis using the enzyme AluI and were
identical to that previously described for R. prowazekii (11). Sequence
determinations were performed by using an automated laser fluorescent DNA
sequencer as previously described (12). The citrate synthase and rOmpB
sequences obtained from the lice had 100% homology with that of R.
prowazekii strain Breinl. Of the 10 tested, two lice from the same patient
(four) were positive.

Cause, Symptoms, and Diagnosis

Social conditions are critical factors influencing the reemergence of
disease. Louse infestation occurs when cold weather, poor hygiene, and
poverty are prevalent; these conditions have been present in refugee camps
in Rwanda and Zaire recently (13,14). Louse infestation has also been found
in several eastern European countries and in homeless persons in western
Europe (15).

Epidemic typhus was suspected in a refugee camp in Goma, Zaire, in 1994,
but the outbreak was unconfirmed (14). Typhus is usually exanthematic, and
a careful clinical examination will find a rash in more than half of the
cases. In the present series, clinical data were recorded retrospectively
mainly on the basis of a nurse's report and are probably incomplete
(Table). In an outbreak, looking for exanthema is critical for typhus
suspicion. The typhus exanthema is frequently purpuric and is observed even
on dark skin in 33% of cases (6). The other typical symptoms are neurologic
signs including seizures, coma, and mental confusion, which gave the
disease its name (ORIG: from the Greek word "typhos," which means smoke,
cloud, stupor arising from fever). Neurologic involvement was noted in
seven of the nine cases: symptoms included coma, seizures, mental
confusion, and delirium. Rash was described in only two patients (Figure);
splenomegaly in three patients; cough in three patients; dyspnea in three
patients; and hypotension in four patients. Two patients died. The other
patients recovered rapidly after receiving chloramphenicol. The prevalence
of pulmonary symptoms is high in general as noticed here.
of pulmonary symptoms is high in general as noticed here.

In situations like those observed in this jail, one can suspect either
murine or epidemic typhus. Murine typhus is less severe. However, in
poor hygienic conditions, rats are prevalent, and the risk exists for
both diseases. Consequently, in such situations it is critical to
discriminate between R. prowazekii and R. typhi infections because they 
do not have the same epidemic potential. Diagnosis is usually 
provided by microimmunofluorescence; in some cases antibody levels are
sufficient to differentiate between the two diseases. IgG titers are
usually different, but IgM titers are not. When, as in Patients Four and
Eight, antibodies are at the same level, cross-adsorption, a tedious 
and expensive procedure requiring large amounts of antigens and serum
(not available in our study [16]), can differentiate between the two
diseases. The use of arthropod vectors for gene amplification and disease
recognition has been reported (17). In a case of laboratory-acquired human
typhus, diagnosis was confirmed by PCR (18). However, in the present work,
we report for the first time the use of the louse in diagnosing epidemic
typhus in the field.

[Image] 
Figures Not Available in Ascii
Figure. Rash in a man with epidemic typhus in Burundi.

The confirmation of a typhus outbreak in Burundi is of concern, given the
relative political instability in this area of the world. A preliminary
report from the World Health Organization discusses a current large
outbreak in Burundi with an estimated 24,000 cases (1). It is uncertain if
the outbreak we observed is related to the current epidemic, but our
present work confirms continuing cycles of louse-borne typhus in Burundi.
Delousing (14) is critical to typhus prevention. The treatment for typhus
is simple and inexpensive: a single dose of 200 mg of doxycycline provides
cure (19).

We stress the major risk for exanthematic typhus in central eastern Africa
including Burundi, Zaire, and Rwanda and the importance of sending lice to
reference laboratories to identify the pathogens when a typhus outbreak is
observed. Molecular identification by PCR and sequencing offers a rapid,
sensitive, and specific identification method for Rickettsia, even when
epidemiologic investigations are undertaken.

References

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     rickettsial diseases. Boca Raton (FL): CRC Press; 1991. p. 51-61.
  3. McDade JE. Evidence of Rickettsia prowazekii infections in the United
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     Epidemiol Rec 1986;7:49-50.
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Emerging Infectious Diseases
National Center for Infectious Diseases
Centers for Disease Control and Prevention
Atlanta, GA

URL: ftp://ftp.cdc.gov/pub/EID/vol3no3/ascii/raoult.txt