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Ectoparasite Endoparasite. 1/26/2007. Xenopsylla cheopis. Rattus rattus. Yersinia pestis.

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Xenopsylla cheopis

Rattus rattus

Yersinia pestis


Anopheles gambieae

Plasmodium falciparum


Female Hyalomma tick

Crimean-Congo Hemorrhagic Fever


Pediculus humanus corporis

Napoleon retreating from Russia



cdc traveler s health warning
CDC Traveler’s health warning
  • Malaria, yellow fever, traveler’s diarrhea, cholera, typhoid fever, dengue, filariasis, leishmaniasis, onchocerciasis, rift valley fever, African trypansomiasis, rickettsial infections, schostosomiasis, tuberculosis, polio, HIV, HBV
who burundi profile
WHO Burundi profile
  • Since the beginning of 2004, up to 140,000 internally displaced persons and some 80,400 refugees have returned spontaneously or with assistance. However, an overall estimate of 69% of the population lives below the absolute poverty line. several parts of the country still face armed unrest and a large group of Burundian displaced and refugees are unable to return home.
  • Crisis involving: the whole population
quick stats
Quick Stats
  • Under five crude mortality far exceeds Emergency criteria
  • Malaria is responsible for >50% of deaths under five
  • Less than 50% have access to potable water
  • Food insecurity widespread
  • HIV/AIDS 6%
  • 80% of the population lives close to medical facilities which are inadequate, of poor quality and expensive.
a little poetic license
A little poetic license…
  • Chaos still reigns in the wake of ongoing conflict between Hutu and Tutsi. 760,000 people inhabit refugee camps in squalor. There is not enough water, the population is malnourished. Epidemics have broken out already in the early 90’s. The year is 1995.
in the seclusion of switzerland
In the seclusion of Switzerland
  • A middle aged nurse recently back from Burundi walks into your clinic. He complains of fever, rash, myalgias and fatigue. He tells you that he was working in poor conditions in the N’Gozi prison in Northern Burundi which houses about 1200 people. It was overcrowded and full of lice and they had no medicine.
common causes of fevers in returned travellers
Common causes of fevers in returned travellers
  • Malaria 27-42%
  • Dengue, viral hepatitis, typhoid fever, enteric pathogens.
  • 25% no diagnosis made
  • Mandell’s
hospital course
Hospital course
  • He was admitted on the sixth day of disease with headache as his chief complaint. T 40.7° C. P 108. RR 36. Blood pressure 126/66 mm. NAD. No rash. Otherwise unremarkable. WBC 7.5.

  • Hospital course.—Throughout the first week of hospitalization the patient's fever remained high and a rash appeared, with intense conjunctival injection and the development of petechiae in the left conjunctival sac. The patient, actively delirious, became very talkative and attempted to get out of bed. He eventually needed IV fluids.
the rash
The rash

Raoult et al.

  • On the 13th day he became more stuporous and then semicomatose. He lay with half-opened eyes, breathing quietly. Facial grimaces and grinding of the teeth were noted. Around day 17, the rash gradually faded out during this period and the conjunctival suffusion disappeared.
  • In the next 2 days he was able to obey simple commands. It was evident that he was almost totally deaf. On the 20th day his temperature reached normal levels.
  • From this time onward improvement in his general condition was steady but slow. The ability to stand and walk unassisted returned before the ability to form words. At the time of discharge 68 days after the onset of the disease, speech was slow, expressionless, and labored. Hyperactive reflexes were still present in the lower extremities, but the positive Babinski phenomenon had disappeared.
in retrospect you wish you had done something
In retrospect, you wish you had done something…

So, you were lucky that the patient lived. Now from the natural history, what do you think it could have been?

Rickettsia prowazekii

Scrub typhus

Borrellia recurrentis

Bartonella quintana


Rift Valley fever

Typhoid fever

N. meningiditis


Yellow fever


African trypanosomiasis

West Nile

Rickettsia africae


Katayama fever

The Unknown…


katayama fever schistosomiasis
Katayama fever- Schistosomiasis
  • Fresh water exposure in rural areas with snails
  • Fevers, chills, myalgias, arthralgias, cough, headache, diarrhea, lymphadenopathy, hepatosplenomegaly

Return to DDx

rickettsia africae
Rickettsia africae
  • Throughout subsaharan Africa
  • Vector Amblyomma variegatum
  • Eschars prominent in this rickettsiosis
  • HA, fever, myalgia, rash lymphadenitis

Return to DDx

african trypanosomiasis
Vector – glossina morsitans

Fever, malaise, headache. Untreated, death ensues in weeks to months.

Return to DDx

African Trypanosomiasis
yellow fever
Aedes aegypti

Self limited to hemorrhagic fever

Fever, headache, myalgias, followed by remission of symptoms and then renewal with back pain, n/v, abdominal pain, somnolence and prostration. GIB, purpura, jaundice and sometimes death can ensue.

Return to DDx

Yellow Fever:
break bone fever dengue
A flavivirus

Aedes aegypti

Dengue –HA, myalgia, rash, URI sxs. Fever may have saddleback pattern.

Dengue hemorrhagic fever – hemorrhage and hypovolemic shock. Indistinguishable early, but then progresses

Return to DDx

Break bone fever: Dengue
west nile virus
Culex pipiens

Acute high fever, rigors, headache, myalgia, arthralgia

May develop assymetric acute flaccid paralysis

Return to DDx

West Nile Virus
malaria esp plasmodium falciparum
Malaria – esp Plasmodium falciparum
  • Malaria transmission can occur all year in the African Great Lakes region
  • Mosquitoes do not like altitude
  • Can have a classic paroxysmal fever in tertian or quartan cycles
plague yersinia pestis
Plague : Yersinia pestis

Global distribution

Madagascar, Tanzania and DR of Congo leading the pack

Vector Xenopsylla cheopis

Bubonic plague- Fever, chills, weakness and headache, then the buboe

Sepicemic plague- the above without necessarily the lymphadenitis

Pneumonic plague- the above with a severe contagious pneumonia

Return to DDx

neisseria meningiditis
Neisseria meningiditis
  • Epidemics occur in crowded conditions throughout the world- especially during the dry season in the Meningitis belt
  • Vector – humans by respiratory droplets
  • Bacteremia without sepsis – URI w or w/o exanthem
  • Meningiococcemia sans meningitis
  • Meningitis w or w/o meningococcemia

Return to DDx

From the CDC

typhoid fever salmonella typhii
Typhoid fever: Salmonella typhii
  • Enlargement of Peyer’s patches is the historical way it was differentiated from typhus
  • Vector: children and Typhoid Mary
  • Endemic in South Asia, SE Asia, S&C America, Africa
  • Fevers, chills, headache, myalgia, abdominal pain, diarrhea

Return to DDx

rift valley fever
Rift Valley Fever
  • Transmittted by Aedes mcintoshi
  • Epidemics after flooding
  • It also can be transmitted by direct contact with animal blood.
  • Fever, hemorrhage, jaundice, hepatitis, encephalitis.

Return to DDx

leptospirosis leptospira interrogans
Leptospirosis: Leptospira interrogans
  • Extreme variation in presentation
  • Confused with yellow fever in the 19th century
  • Endemic globally
  • Epidemics occur around times of heavy rainfall
  • Infection from urine from small animals
  • High fever, septicemic picture with headache, myalgias, abdominal pain, n/v/ diarrhea. Progressing to jaundice, renal failure, arrhythmias, respiratory failure, aseptic meningitis

Return to DDx

trench fever bartonella quintana
Trench FeverBartonella quintana
  • Lower mortality especially compared to Oroya fever
  • Vector Pediculus humanus
  • Around 5 episodes of 5 days of fever
  • Sudden onset fever, rigor with headache, myalgia, arthralgia, rash
  • Global distribution

Return to DDx

epidemic relapsing fever borrellia recurrentis
Epidemic relapsing fever:Borrellia Recurrentis
  • Vector Pediculus humanus
  • Infection comes from smashing the bugs into the wound
  • Acute onset of high fever, rigors, headache, myalgia, arthralgia, lethargy
  • Global distribution

Return to DDx

epidemic typhus rickettsia prowazekii
Epidemic typhus: Rickettsia prowazekii
  • Transmitted through the vector of body lice
  • Recrudescence may occur years later (Brill Zinsser)
  • Endemic in Andes, Burundi, Rwanda, Russia, Senagal, Algeria, France, major epidemics in North Africa and Italy in the last century.
  • Reservoir Glaucomys volans.
  • Rash, fever, HA, stupor, cough, myalgias.

Return to DDx

scrub typhus orientia tsutsugamushi
Scrub typhus:Orientia tsutsugamushi
  • Triangle delineated by Hokkaido, Eastern Australia, and the Indian subcontinent.
  • Vector: chiggers (thrombiculid mite larvae)
  • Fever, mental changes, inoculation eschar, lymphadenopathy.

Return to DDx

the unknown
Ebola and Marburg are filoviruses in a group that is considered “hot”

It is generally believed that diseases with a predilection for humans need to be somewhat attenuated with respects to virulence or an epidemic cannot be sustained.

Return to DDx

Five health workers, in head-to-toe "Ebola suits," on their way to pick up a man stricken ill in the Marburg virus outbreakin Uige, Angola.(Photo: Florence Panoussian / AFP /Getty Images)

The Unknown
  • Lumbar puncture - pleocytosis
  • LFT’s – elevated with increased bilirubin
  • CBC – leukopenic, thrombocytopenic
  • Serum protein - low
  • Blood culture - negative
  • Weil Felix reaction - negative
  • PCR and indirect IFA positive for…
  • Typhos in the Greek which means smoky or hazy
  • Describes a handful of syndromes caused by Rickettsial species.
  • Rickettisals are intracellular bacteria
rickettsia prowazekii
The only epidemic rickettsial disease

Spread by lice and shortens their life span too

Responsible for many epidemics in history

Brill Zinsser recrudescence may occur years later

Southern flying squirrels are an extrahuman reservoir

Rickettsia prowazekii
  • Like other Rickettsiae, it enters through endothelial cells, but unlike many of the others, it does not polymerize actin in invading adjacent cells. Organisms multiply until cells burst which sets up for an intravascular inflammatory reaction, further spread and petechial hemorrhage. Little is known about potential toxins or other virulence mechanisms.
clinical symptoms
Clinical Symptoms
  • HA
  • Chills
  • Myalgias
  • Rash- erythematous macules ~ day 5
  • Conjunctival injection
  • Rales
  • Delirium
  • Cough
  • Gangrene
  • Coma
  • death
diagnosis and treatment
Diagnosis and Treatment
  • Historically, the Weil-Felix reaction was important, but it is not sensitive nor specific.
  • Serology and PCR are used
  • Treatment – Doxycycline and chloramphenicol. Also, kill the lice.
  • No vaccine is available
the vector
Pediculus humanus corporis

Louse Times - Wanted ads

Looking for a warm body in a cold place. I like inseams and layered clothes. I am not into rich people but like to meet a lot of people. Poor grooming is not a turnoff. Must like nits!!!

The Vector
breaking news
Breaking news
  • In Burundi, thousands are coming down with fevers of unknown origin. Many of them are dying. Especially affected are the jails Ngozi, Bururi and Gitega. The locals call it “sutama.”
You cringe a bit as this is now 2 years after you presented your case of epidemic typhus at Grand Rounds
  • Wishing to redeem yourself, you volunteer to go down to lead the outbreak investigation.
the jails are worse
And lice are crawling everywhere

About 50% got sick with sutama in N’Gozi and Bururi where there were no antibiotics. 12% were dying.

The jails are worse
being a good scientist
Being a good scientist…
  • You remember that this could still have a significant differential
  • If lice are the vectors, there are three epidemic diseases they spread: epidemic typhus, trench fever, and epidemic relapsing fever.
you grind up the vermin
You grind up the vermin
  • And get blood from the victims and the data show…
  • * The typhus epidemic first signalled by WHO authorities in Burundi in early February is reported to be spreading. The government regroupment villages are said to be hardest hit because of overcrowding and poor sanitation and health structures. In some villages, as many as 500 to 1,000 new cases are reported daily. Worst hit areas are the provinces of Kayanza, Muramvua and Karuzi. WHO believes some 340,000 people are at risk and that if the epidemic is unchecked it could evolve into the largest typhus outbreak since World War II. WHO has flown in 150,000 tablets to treat typhus cases; however the related issues of sanitation and health conditions will have to be addressed immediately in order to contain the epidemic.
burundi louse borne epidemic
Burundi louse borne epidemic
  • 45558 cases were clinically diagnosed
  • 8% of cases were believed to be B. quintana.
  • Mandell et al, Principles and Practice of Infectious Diseases
  • Raoult et al, Outbreak of epidemic typhus. The Lancet 1998(352):353
  • Raoult et al, The History of epidemic typhus. Infect Dis Clin N Am 18 (2004) 127–140
  • Bise et al, Epidemic typhus in a prison in Burundi, Trans R S Trop Med Hyg (1997) 91:133-134.