Communicable Diseases

  1. Selected Water-borne Diseases  
  2. Selected Helminthic Diseases
  3. Selected Miscellaneous Diseases

 

 

 

 

 

 

 

 

 

 

 


Selected Water-borne Diseases  

 
1. typhoid fever 
 
     agent:         Salmonella typhi
     reservoir:     human 
     transmission:  indirect, vectors (flies)
     symptoms:      can be asymptomatic
                    fever, gastroenteritis, nosebleeds 
                    rose spots (red patches on abdomen) 
 
2. paratyphoid 
   fever 
 
     agent:         3 main groups of Salmonella paratyphi 
     reservoir:     primarily human
     transmission:  same as typhoid fever 
     symptoms:      similar to typhoid, but paratyphoid is much less virulent
 
3. Cholera  
 
     agent:         Vibrio cholera
     reservoir:     human; perhaps environmental reservoirs
     transmission:  fecal (or vomitus)
                    [direct, indirect (food, water, flies)] 
     symptoms:      sudden and severe diarrhea
                    vomiting, severe dehydration, death
 
4. Shigellosis      (also known as bacillary dysentary)  
    (dysentary) =   acute colitis with diarrhea
 
     agent:         4 groups of genus Shigella (bacteria)
     reservoir:     humans; primates 
     transmission:  fecal [direct, indirect (food, water, flies)]
     symptoms:      diarrhea, fever, nausea
                    stools contain blood, mucus, and pus
 
5. Amebiasis        (amebic dysentary)  
 
     agent:         Entamoeba histolytica (a protozoon)
     reservoir:     human; usually a chronically ill 
                     or asymptomatic carrier
                                                            Patients with acute amebiasis actually pose a low risk of transmission. 
     transmission:  fecal [direct, indirect (food, water, flies)]
                    acute patients pose limited danger
                           (absence of cysts) 
     symptoms:      often asymptomatic; fever, chills, diarrhea
                    stools contain blood, mucus 
 
6. Giardiasis  
 
     agent:         Giardia lamblia (protozoan)
     reservoir:     human; possibly other animals 
     transmission:  fecal  (water or food) (cysts resist treatment)
     symptoms:      often asymptomatic; diarrhea, cramps, fatigue 
 
 
 

   

 

Selected Helminthic Diseases  

 
1. Trichinosis 
 
     agent:         Trichanella spiralis
     reservoir:     pigs, wild boar, bears, foxes, wolves, rats
     transmission:  eating infected animals
     symptoms:      nausea, gastroenteritis 
                    (must thoroughly cook pork >150 deg. F)
 
 
2. Ascariasis (roundworms) 
 
     agent:         primarily Ascaris lumbricoides 
     reservoir:     humans, infected soils
     transmission:  not person to person
The eggs of Ascariasis are not immediately infective. 
                    ingestion of infective eggs (soil)
     symptoms:      live worms in stool 
                    varied: coughing, fever, nutrition
 
 
3. Schistosomiasis  (blood flukes)  
 
     agent:         Schistosoma (4 species)
     reservoir:     humans (and various animals)
     transmission:  vectors (biological) 
                    larvae from snail infested waters 
     symptoms:      varied 
 
 
4. Other helminthic diseases                                
                                                      
   a. beef tapeworm         Taenia saginata
 
   b. pork tapeworm         Taenia solium
 
   c. fish tapeworm         Diphyllobothrium latum             
 
   d. dracunculiasis                                      
      (dracontiasis)        Dracunculus medinensis      
 
   e. ancylostomiasis                                     
      (hookworm)            Ancylostoma                 
 
   f. enterobiasis                                        
      (pinworm)             Enterobias                  
                                                           
 
   
 
   

Selected Miscellaneous Diseases  

 
1. Ringworm
 
     agent:        Microsporum, Trichophyton, others (fungi)
Ringworm is not actually a helminthic worm.  
It is invariably a fungus.
     reservoir:    infected human or animal
     transmission: physical contact
     symptoms:     dermatitis (athlete's foot,jock itch, etc.)
          control: cleaning floors, showers, clothing
 
 
2. Tetanus
 
     agent:        Clostridium tetani
     reservoir:    soil, street dust, animal feces
     transmission: typically by entrance in a wound
     symptoms:     muscular contractions, spasms
                   case fatality can be high                    
          control: immunization, cleansing wounds
 
 
3. Anthrax
 
     agent:        Bacillus anthracis 
     reservoir:    cattle, sheep, goats, horses, swine
     transmission: contact with hides or meat, flies
     symptoms:     itchy skin; complications if untreated
          control: vaccine, sanitation, dust control
 
 
4. Leprosy 
 
     agent:        Mycobacterium leprae
     reservoir:    humans
     transmission: not clearly established
                   prolonged contact is important
Leprosy has an extremely long incubation period
     symptoms:     Leprosy is a disease of the skin, nerves, and nasal musosa.  
                   symptoms vary
 
 

 

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