It is a type of Infectious disease caused by the Rickettsia genus of bacteria.
Rickettsiae are a heterogeneous group of small, obligately intracellular, gram-negative coccobacilli and short bacilli, most of which are transmitted by a tick, mite, flea, or louse vector.
Except in the case of louse-borne typhus, humans are incidental hosts.
Paragonimus is a lung fluke (flatworm) that infects the lungs of humans after eating an infected raw or undercooked crab or crayfish. Less frequent, but more serious cases of paragonimiasis occur when the parasite travels to the central nervous system instead of the lungs.
Although rare, paragonimiasis has been acquired in the United States, with multiple cases reported from the Midwest. Treatment for paragonimiasis is available from a physician after an accurate diagnosis is made.
Paragonimus is a lung fluke (flatworm) that infects the lungs of humans after eating an infected raw or undercooked crab or crayfish. Less frequent, but more serious cases of paragonimiasis occur when the parasite travels to the central nervous system instead of the lungs.
Although rare, paragonimiasis has been acquired in the United States, with multiple cases reported from the Midwest. Treatment for paragonimiasis is available from a physician after an accurate diagnosis is made.
Poxviruses are brick or oval-shaped viruses with large double-stranded DNA genomes. Poxviruses exist throughout the world and cause disease in humans and many other types of animals. Poxvirus infections typically result in the formation of lesions, skin nodules, or disseminated rash.
West Nile virus (WNV) is an infectious disease that first appeared in the United States in 1999. WNV is spread when mosquitos infected with the disease bite humans or animals. People who contract WNV usually have no symptoms or mild symptoms. Those with symptoms may have a fever, headache, body aches, skin rash or swollen lymph glands.
If West Nile virus enters the brain, it can be deadly. It may cause inflammation of the brain, called encephalitis, or inflammation of the tissue that surrounds the brain and spinal cord, called meningitis.
http://www.nlm.nih.gov/medlineplus/westnilevirus.html
Poxviruses are brick or oval-shaped viruses with large double-stranded DNA genomes. Poxviruses exist throughout the world and cause disease in humans and many other types of animals. Poxvirus infections typically result in the formation of lesions, skin nodules, or disseminated rash.
West Nile virus (WNV) is an infectious disease that first appeared in the United States in 1999. WNV is spread when mosquitos infected with the disease bite humans or animals. People who contract WNV usually have no symptoms or mild symptoms. Those with symptoms may have a fever, headache, body aches, skin rash or swollen lymph glands.
If West Nile virus enters the brain, it can be deadly. It may cause inflammation of the brain, called encephalitis, or inflammation of the tissue that surrounds the brain and spinal cord, called meningitis.
http://www.nlm.nih.gov/medlineplus/westnilevirus.html
Just one bite of a mosquito can take us closer to death. Don't let that happen to anyone. Happy World Malaria Day. The only way to celebrate the occasion of World Malaria Day is by joining hands against this disease.
In this presentation you will find about the zoonotic potential of rabies virus, its impact in terms of DALYs.
Epidemiology and geographical distribution of rabies.
You will learn about the reservoir and source of rabies, transmission of rabies virus.
You will also learn about the virology of rabies virus inculding its family, genus, its structure, its different protein and the replication cycle of rabies virus.
It will also put light on the pathogenesis of rabies virus and different stages of rabies virus infection.
Then it will discuss about the laboratory diagnosis of rabies virus infection in humans as well as in animals including specimen collection, culturing, microscopy, animal inoculation and molecular diagnosis.
After that, you will get information about the prevention and control of rabies and different successful control strategies adopted by several countries of the world.
In the end it will discuss the status of rabies in Pakistan and specially WHO responses to rabies control in pakistan.
Neglected tropical diseases nt ds-kananura-egesa-finalKananura Keneth
We give a highlight of common neglected tropical diseases in Uganda and East Africa region.
Compiled by me (Dr.Keneth Kananura, MBChB,Mak) and my supervisor, Dr. Moses Egesa, PhD-MRC-Uganda)
Arthropods form a major group of disease vectors with mosquitoes, flies, sand flies, lice, fleas, ticks and mites transmitting a huge number of diseases.
Infections and salivary gland disease in pediatric age: how to manage - Slide...WAidid
The slideset by Professor Susanna Esposito aims at explaining how to manage the salivary gland infections in pediatric age, from pathogenesis, to transmission, treatments and vaccination coverage, that should be urgently increased in Italy as well as in EU Countries.
Etiology- genetic mutations, infection, toxin exposure, autoimmunity, atherosclerosis, hypertension, emboli, thrombosis, or diabetes mellitus.
Even after careful study, however, the cause often remains unknown, and the lesion is called idiopathic.
Inflammation of the glomerular capillaries is called glomerulonephritis.
Persistent glomerulonephritis that worsens renal function is always accompanied by interstitial nephritis, renal fibrosis, and tubular atrophy.
Management of liver disease and its complications.pptxjyoti verma
Chronic liver disease (CLD) is a major cause of mortality and morbidity worldwide, accounting for approximately 2 million deaths per year. Moreover, there has been a 46% increase in cirrhosis mortality in the world from 1980 to 2013.
Currently, cirrhosis and liver cancer cause 1.16 million and 788,000 deaths per year globally, respectively, making them the 11th and 16th most common causes of death, respectively.
Together, they are responsible for 3.5% of all deaths worldwide
DEFINITION AND MEASUREMENT Obesity is a state of excess adipose tissue mass. Although often viewed as equivalent to increased body weight, this need not be the case—lean but very muscular individuals may be overweight by numerical standards without having increased adiposity.
Body mass index (BMI), which is equal to weight/height2 (in kg/m2 )
Body weights are distributed continuously in populations, so that choice of a medically meaningful distinction between lean and obese is somewhat arbitrary. Obesity is therefore defined by assessing its linkage to morbidity or mortality
GUIDELINES ON DEAD BODY MANAGEMENT
Scope of the document
Key Facts
Standard Precautions to be followed by health care workers while handling dead bodies of COVID.
Training in infection and prevention control practices
Removal of the body from the isolation room or area
Environmental cleaning and disinfection
Handling of dead body in Mortuary
Drug induced liver injury- pathophysiology and causes.pptxjyoti verma
Liver injury is a possible consequence of
ingestion of any xenobiotic, including industrial toxins, pharmacologic agents, and
complementary and alternative medications (CAMs).
Among patients with acute liver failure, drug-induced liver injury (DILI) is the most common cause.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
2. What is Typhus fever?
• It is a type of Infectious disease caused by the Rickettsia genus of
bacteria.
• Rickettsiae are a heterogeneous group of small, obligately
intracellular, gram-negative coccobacilli and short bacilli, most of
which are transmitted by a tick, mite, flea, or louse vector.
• Except in the case of louse-borne typhus, humans are incidental
hosts.
4. Clinical infections with rickettsiae can be classified according to
(1) the taxonomy and diverse microbial characteristics of the agents, which
belong to seven genera (Rickettsia, Orientia, Ehrlichia, Anaplasma,
Neorickettsia, “Candidatus Neoehrlichia,” and Coxiella);
(2) epidemiology; or
(3) clinical manifestations.
The clinical manifestations of all the acute presentations are similar during
the first 5 days: fever, headache, and myalgias with or without nausea,
vomiting, and cough. As the course progresses, clinical manifestations—
including a macular, maculopapular, or vesicular rash; eschar; pneumonitis;
and meningoencephalitis—vary from one disease to another.
5. Heightened clinical suspicion is based on
• epidemiologic data
• history of exposure to vectors or reservoir animals
• travel to endemic locations
• clinical manifestations (sometimes including rash or eschar), and
• characteristic laboratory findings (including thrombocytopenia,
normal or low white blood cell [WBC] counts, elevated hepatic
enzyme levels, and hyponatremia). Such suspicion should prompt
empirical treatment.
6. EPIDEMIC (LOUSE-BORNE) TYPHUS
• The human body louse (Pediculus humanus corporis) lives in clothing
under poor hygienic conditions and usually in impoverished cold
areas Lice acquire R. prowazekii when they ingest blood from a
rickettsemic patient The rickettsiae multiply in the louse’s midgut
epithelial cells and are shed in its feces.
• The infected louse leaves a febrile person and deposits infected feces
on its subsequent host during its blood meal
• The patient autoinoculates the organisms by scratching. The louse is
killed by the rickettsiae and does not pass R. prowazekii to its
offspring.
7. EPIDEMIOLOGY
• Epidemic typhus haunts regions afflicted by wars and disasters. An outbreak
involved 100,000 people in refugee camps in Burundi in 1997. A small focus was
documented in Russia in 1998, sporadic cases were reported from Algeria, and
frequent outbreaks occurred in Peru and Rwanda.
• Eastern flying squirrels (Glaucomys volans) and their lice and fleas maintain R.
prowazekii in a zoonotic cycle.
• Brill-Zinsser disease is a recrudescent illness occurring years after acute epidemic
typhus, probably as a result of waning immunity.
• R. prowazekii remains latent for years; its reactivation results in sporadic cases of
disease in louse-free populations or in epidemics in louse infested populations.
Recrudescence has been documented after flying squirrel–associated typhus.
Rickettsiae are potential agents of bioterrorism.
8. Clinical Manifestations
After an incubation period of ~1–2 weeks,
• Severe headache, and fever rising rapidly to 38.8°–40.0°C (102°–
104°F).
• Cough is prominent, developing in 70% of patients.
• Myalgias are usually severe.
• A rash begins on the upper trunk, usually on the fifth day, and then
becomes generalized, involving the entire body except the face,
palms, and soles. Initially, this rash is macular; becomes
maculopapular, petechial, and confluent.
9. Clinical features cont.
• Photophobia, with considerable conjunctival injection and eye pain, is
common.
• The tongue may be dry, brown, and furred.
• Confusion and coma are common.
• Skin necrosis and gangrene of the digits
• Interstitial pneumonia may occur in severe cases.
• Patients with untreated infections develop renal insufficiency and
multiorgan involvement.
• Neurologic involvement(12%).
• Infection associated with North American flying squirrels is a milder illness;
whether this milder disease is due to host factors (e.g., better health
status) or attenuated virulence is unknown.
10. Diagnosis and Treatment
• Epidemics can be recognized by the serologic or
immunohistochemical diagnosis of a single case or by detection of R.
prowazekii in a louse found on a patient.
Doxycycline (100 mg bid) is administered orally or—if the patient is
comatose or vomiting— intravenously and continued until 3–5 days
after defervescence.
Under epidemic conditions, a single 200-mg oral dose can be tried
but fails in some cases.
Pregnant patients should be evaluated individually and treated with
chloramphenicol early in pregnancy or, if necessary, with doxycycline
late in pregnancy.
11. ENDEMIC MURINE TYPHUS
• R. typhi is maintained in mammalian host–flea cycles, with rats (Rattus
rattus and R. norvegicus) and the Oriental rat flea (Xenopsylla cheopis) as
the classic zoonotic niche.
Fleas acquire R. typhi from rickettsemic rats and carry the organism
throughout their life span.
Nonimmune rats and humans are infected when rickettsia-laden flea
feces contaminate pruritic bite lesions; less frequently, the flea bite transmits
the organisms.
Transmission can also occur via inhalation of aerosolized rickettsiae from flea
feces. Infected rats appear healthy, although they are rickettsemic for ~2
weeks.
12. Epidemiology
• Murine typhus occurs mainly in Texas and southern California, where
the classic rat–flea cycle is absent and an opossum–cat flea (C. felis)
cycle is prominent.
• Globally, endemic typhus occurs mainly in warm (often coastal) areas
throughout the tropics and subtropics, where it is highly prevalent
though often unrecognized.
• The incidence peaks from April through July in southern Texas and
during the warm months of summer and early fall in other geographic
locations.
13. Clinical Manifestations
The incubation period of experimental murine typhus averages 11 days (range, 8–
16 days).
• Headache, myalgia, arthralgia, nausea, and malaise develop 1–3 days before
onset of chills and fever.
• Nausea and Vomiting. The duration of untreated illness averages 12 days (range,
9–18 days).
• Rash is present in only 13% of patients at presentation for medical care (usually
~4 days after onset of fever), appearing an average of 2 days later in half of the
remaining patients and never appearing in the others.(axilla or the inner surface
of the arm)
Subsequently, the rash becomes maculopapular, involving the trunk more often
than the extremities; it is seldom petechial and rarely involves the face, palms, or
soles. A rash is detected in only 20% of patients with darkly pigmented skin.
14. Clinical manifestations cont.
• Pulmonary involvement is frequently prominent;
• 35% of patients have a hacking, nonproductive cough, and chest radiography have
pulmonary densities due to interstitial pneumonia, pulmonary edema, and pleural
effusions. Bibasilar rales are the most common pulmonary sign.
• Less common clinical manifestations include abdominal pain, confusion, stupor, seizures,
ataxia, coma, and jaundice.
• Clinical laboratory studies
Anemia and leukopenia early in the course,
leukocytosis late in the course,
Thrombocytopenia, hyponatremia, hypoalbuminemia, increased serum levels of hepatic
aminotransferases, and prerenal azotemia.
Complications can include respiratory failure, hematemesis, cerebral hemorrhage, and
hemolysis
15. Diagnosis and Treatment
• Serologic studies of acute- and convalescent-phase serum samples
can provide a diagnosis, and an immunohistochemical method for
identification of typhus group specific antigens in biopsy samples has
been developed.
• When endemic typhus is suspected, patients should be treated
empirically with doxycycline (100 mg twice daily by mouth for 7–15
days). Chloramphenicol and ciprofloxacin are less effective
alternatives.
16. SCRUB TYPHUS
Epidemiology and pathophysiology
O. tsutsugamushi is maintained by transovarial transmission in trombiculid
mites.
After hatching, infected larval mites (chiggers, the only stage that feeds on
a host) inoculate organisms into the skin.
Infected chiggers are particularly likely to be found in areas of heavy scrub
vegetation during the wet season, when mites lay eggs.
Scrub typhus is endemic and reemerging in eastern and southern Asia,
northern Australia, and islands of the western Pacific and Indian Oceans.
17. Clinical Manifestations
Illness varies from mild and self limiting to fatal.
After an incubation period of 6–21 days, onset is characterized
• Fever, headache, myalgia, cough, and gastrointestinal symptoms.
• The classic case description includes an eschar where the chigger has fed,
regional lymphadenopathy, and a maculopapular rash—signs that are
seldom seen in indigenous patients. In fact, fewer than 50% of Westerners
develop an eschar, and fewer than 40% develop a rash (on day 4–6 of
illness).
• Encephalitis and interstitial pneumonia due to vascular injury. The case–
fatality rate for untreated classic cases is 7% but would probably be lower if
all mild cases were diagnosed.
18. Diagnosis and Treatment
• Serologic assays (indirect fluorescent antibody, indirect
immunoperoxidase, and enzyme immunoassays) are the mainstays of
laboratory diagnosis.
• PCR amplification of Orientia genes from eschars and blood also is
effective.
• Patients are treated with oral doxycycline (100 mg twice daily for 7–
15 days), azithromycin (500 mg for 3 days), or chloramphenicol (500
mg four times daily for 7–15 days).