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Learning objectives

  • Identify common parasites that cause infections of the circulatory and lymphatic systems
  • Compare the major characteristics of specific parasitic diseases affecting the circulatory and lymphatic systems

Some protozoa and parasitic flukes are also capable of causing infections of the human circulatory system. Although these infections are rare in the US, they continue to cause widespread suffering in the developing world today. Fungal infections of the circulatory system are very rare. Therefore, they are not discussed in this chapter.

Malaria

Despite more than a century of intense research and clinical advancements, malaria remains one of the most important infectious diseases in the world today. Its widespread distribution places more than half of the world’s population in jeopardy. In 2015, the WHO estimated there were about 214 million cases of malaria worldwide, resulting in about 438,000 deaths; about 88% of cases and 91% of deaths occurred in Africa. World Health Organization. “World Malaria Report 2015: Summary.” 2015. http://www.who.int/malaria/publications/world-malaria-report-2015/report/en/. Accessed July 28, 2016. Although malaria is not currently a major threat in the US, the possibility of its reintroduction is a concern. Malaria is caused by several protozoan parasites in the genus Plasmodium : P. falciparum, P. knowlesi, P. malariae, P. ovale, and P. vivax. Plasmodium primarily infect red blood cells and are transmitted through the bite of Anopheles mosquito es.

Currently, P. falciparum is the most common and most lethal cause of malaria, often called falciparum malaria. Falciparum malaria is widespread in highly populated regions of Africa and Asia, putting many people at risk for the most severe form of the disease.

The classic signs and symptoms of malaria are cycles of extreme fever and chills. The sudden, violent symptoms of malaria start with malaise, abrupt chills, and fever (39–41° C [102.2–105.8 °F]), rapid andfaint pulse, polyuria, headache, myalgia, nausea, and vomiting. After 2 to 6 hours of these symptoms, the fever falls, and profuse sweating occurs for 2 to 3 hours, followed by extreme fatigue. These symptoms are a result of Plasmodium emerging from red blood cells synchronously, leading to simultaneous rupture of a large number of red blood cells, resulting in damage to the spleen, liver, lymph nodes, and bone marrow. The organ damage resulting from hemolysis causes patients to develop sludge blood (i.e., blood in which the red blood cells agglutinate into clumps) that can lead to lack of oxygen, necrosis of blood vessels, organ failure, and death.

In established infections, malarial cycles of fever and chills typically occur every 2 days in the disease described as tertian malaria , which is caused by P. vivax and P. ovale . The cycles occur every 3 days in the disease described as quartan malaria , which is caused by P. malariae . These intervals may vary among cases.

Plasmodium has a complex life cycle that includes several developmental stages alternately produced in mosquitoes and humans ( [link] ). When an infected mosquito takes a blood meal, sporozoites in the mosquito salivary gland are injected into the host’s blood. These parasites circulate to the liver, where they develop into schizonts. The schizonts then undergo schizogony , resulting in the release of many merozoites at once. The merozoites move to the bloodstream and infect red blood cells. Inside red blood cells, merozoites develop into trophozoites that produce more merozoites. The synchronous release of merozoites from red blood cells in the evening leads to the symptoms of malaria.

Questions & Answers

can you please differentiate between vacuoles and inclusion bodies
Noor Reply
vacuoles consists of watery solution called cell sap while bodies are organelles
Prince
5 difference please
Noor
Archaea is an odd type of bacteria that live in extreme environments; high salt, high temperature etc. usually called extremophiles.
Danesia Reply
you know anyone that has delt with enterobacter agglomerans.
Vernon
it is a type of gram negative bacteria and its ubiquitous mostly isolated from plant stuffs and also from faecal material of animals. I heard the name pantoea . it is bacillus in structure.
Sujan
What are the classification of microorganisms
Portia Reply
Basic classification are eukaryotic and prokaryotic..
micro organisms are classified into three namely: Archaea, eukaryote and prokaryotic organisms
Blandine
Yay that's right
what is archaea
Ateeq
I've got an issue with the message view
Frank Reply
Is there any effective way to learn microbiology.
Frank Reply
I have some basic knowledge of biology. I mean i'm totally beginner in that field.
Frank
Assuming that i'm interested in neuroscience. What is the best way to master that particular subject.
Frank
Hi
Can you wait me just a minute
Iam apologies for guidance you in neuroscience.. I'm not physician.. I'm microbiologist
My pleasure to join to you
Let's begin a conversation
Frank Reply
What would be saying
?
Akram
do you know anything about microbiology
diana
I have so much studying to catch up on🙄
Britnee
any study tips
Britnee
Yas of course
What would you like to know
well i'm studying Pharmacy second year and i just started With Microbiology
diana
if you have any basics to tell us 🤷🏻‍♀️ would be helpful
diana
Yas, first you must know that you will have a very easy lecture..
In second stage you will try to learn the type of microbiology
A simple definition for microbiology
In second stage you will try to learn the type of microbiology.. you must learn the bacteria..its structure.. Classification of bacteria according to shape..
It's so easy
What triggers the natural killer cells
jenipher Reply
microbiology is the study of science which deals with study of microorganism e.g .virus,bacteria
sufian Reply
microbiology is a branch of science that deals with invisible microorganisms.
Abdinur
microbiology is the branch of science which deals with the study of organisms too small to be seen with the naked eye
Andrre
what is microbiology
Safwan Reply
history of microbiology
julie
give all details about cell
Samim Reply
Give me another names for all hypersensitivity
Don Reply
Give me the modern father of microbiology
Don
Antonie van Leeuwenhoek
RITU
Louis pasteur is father of modern microbiology Antonie van Leeuwenhoek is only the father of microbiology
Sujan
Antonie van Leeuwenhoek was the first person to observe the mos. whereas pasteur is the one who described about the vaccine , pasteurization etc.
Sujan
what is the virulence factor
mukhtar Reply
is the abilityof pathogen that cause disease
mary
classification of bacteria
Divya Reply
are classified into 5 as follow 1= bacilli 2= vibro 3= spirilla 4= cocci 5= spirochaetes.
Abdulkareem
this one is on the basis of morphological structure
Sujan
gram positive and gram negative according to gram staining
Sujan
u can find on the basis of temperature resistance and oxygen tolerance
Sujan
good
ANAS
on basis of oxygen requirement they could be categorized as Aerobic anaerobic facultative aerobes microaerophilic
ANAS
bacteria are classified into the three type according to their shape 1.Round cocci 2.Rod bacilli 3. spiral
mukhtar
sorry to say but for microbes there is no facultative aerobes instead it must b facultative anaerobic and obligatory anaerobic, aerotolerant
Sujan
Which ones are the microaerophilic
Godwin
what is the difference between krebs cycle and calvin cycle
Baye Reply

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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