Disease is an unusual condition which affects the organism causing disorders in the structure or in the functioning (Burrows, Scarpelli, 2017). There are two categories in diseases known as infectious/communicable and non infectious/non communicable diseases (Burrows, Scarpelli, 2017). Non infectious diseases are also known as chronic diseases due to its long lasting and slowly progressing nature. Non infectious diseases occur due genetic abnormalities and environmental exposure (Encyclopedia Britannica, 2018). Infectious diseases are transmittable from one organism to another due to which the causative agent is disseminated directly or indirectly (Encyclopedia Britannica, 2018).
An infectious disease occurs due to disease causing organisms. The four major causative agents are virus, bacteria, protozoa and fungi (Mackean, Jones, 1987). These microorganisms enter the host and begin the replication of microorganisms disrupting the regular cell processing in the body resulting symptoms that are specific to the pathogen. Also infectious diseases are transmittable from one organism to another. (William, Scarpelli, 2017). Infectious diseases can be transmitted through various methods like drinking contaminated water and contaminated food, airborne, contact (contagious-sexually transmitted and skin to skin), insect and animal vectors, mother to unborn child (baby) and contaminated hypodermic needles (Mackean, Jones, 1987). Infectious diseases can be prevented through improving personal hygiene (hygiene of eye, ears, respiratory system, genital organs), controlling vectors (insecticides) and usage of protections(condoms).
Non infectious diseases are non transmittable diseases which last for a long period of time caused due to gene mutations, lifestyle factors and environmental toxins. Some risk factors occur due to unhealthy diets, lack of physical activities, smoking and consumption of excessive alcohol (Marcin, 2018). The World health Organization (2013) recognized four major non communicable/infectious diseases. Which were cardiovascular diseases, cancers, chronic respiratory diseases and diabetes. non infectious diseases can be prevented through reducing the intake of harmful alcohols and tobacco, introducing physical activities, prevalence of raised blood pressure, educating people about non infectious diseases, reducing salt intake and reducing the mortality of non infectious diseases( World Health Organization, 2018).
Malaria is mosquito borne, protozoal infection spread by the female anopheles mosquito (Hossain, 2016, p.87 ).
An infected female anopheles mosquito during a blood meal inoculates sporozoites into the human host. The sporozoite invades the liver cell and mature into schizonts which ruptures and releases the merozoites .The merozoites start to replicate resulting the liver cell to burst and release lots of merozoites which releases to the blood stream and invades the red blood cells turning into trophozoite where replications’ occur and mature into schizonts which releases lots more merozoites(asexual cycle).some parasites undergoes a process differentiating male and female parasites which is known as the erythrocytic stages (gametocytes) these parasites are responsible for the clinical manifest of the disease ,the female gametocytes and male gametocytes are again ingested by a female anopheles mosquito. This whole process take 48hours to complete. (Mackean , Jones, 1987).
It has four causative agents known as plasmodium falciparum, plasmodium vivax, plasmodium malariae, plasmodium ovale.There are three types of malaria. Tertian malaria, Quartan malaria and Aperiodic malaria. Tertian malaria is caused by plasmodium vivax and plasmodium ovale, Quartan malaria is caused by plasmodium malariae and aperiodic malaria is caused by plasmodium falciparum (Hossain, Hossain, 2016).The infective stage of malaria is known as sporozoites and the diagnostic stage as gametocytes. Malaria tend to show its symptoms after 10 fourteen days of been infected(Mackean, Jones, 1987).Malaria symptoms are high fever(after every 48 hours with chills and riqors)known as the hot stage, shivering(cold stage), sweating(sweating stage), diarrhea(sometime blood mixed), vomiting, jaundice, anemia and thrombocytopenia(also can cause liver failure)(Hossain, Hossain, 2016).this infection is diagnosed by examining for the thick film which helps to detect the organisms and the thin films which helps to identify the species(falciparum, vivax, ovale, malariae) .Rapid diagnostic test(RDT) for detecting plasmodium falciparum. Less percentage of hemoglobin(anemia) and less blood glucose level(hypoglycemia)(Hossain, Hossain, 2016).malaria could be prevented by using drugs to kill malaria parasite in the blood and liver of infected people, prevention of mosquitoes from breeding, usage of insecticides and bed nets and prompt treatment with artemisinin-based combination therapy. The World Health Organization(2017)stated malaria is estimated to decrease by 18% from 76 to 63 cases per 1000 population at risk between 2010 to 2016.acccording to the latest world malaria report 216 million cases of malaria was reported and 47% of it was reported from South East Asia region.
Dengue is also a mosquito borne diseases(world health organization, 2018). The vectors of the disease is known as Aedes aegypti and aedes albopictus(female) mosquito. The causative agent is Dengue virus which is a flavi virus. It has 4 serotypes.
Aedes mosquito has a life span of 2 weeks (depending on the environmental conditions) (Hossain, Hossain, 2015). There are four main stages of the life cycle. Egg, Larva, Pupa and Adult. The eggs are laid in water bodies and hatches with 48 hour releasing the larvae. The larva (plural-larvae) feeds on the microorganisms and organic matters in the water body. The larvae shed their skin four times, each time growing larger, on the fourth shed turning into pupa. Pupa is a none feeding stage but mobile. During this time period the mosquito charges into an adult it’s a similar process to the metamorphosis seen in butterflies. The adult mosquito rest on the surface of the water body for a while allowing the body parts to harden afterward blood feeding mating does not occur for a couple of days(The American Mosquito Control Association, 2018). Clinical features(symptoms) of dengue consists of high fever, backache, headache, generalized pain(break-bone fever), skin rashers, nausea, vomiting and pain on eye movement(Hossain, Hossain, 2016).dengue is diagnosed by running a blood test to check for Ns1 antigen in the first five days and after five days the IgM and IgG levels are checked. High level of IgM indicating acute and high level of IgM indicating the disease is pasted (Hossain, Hossain, 2015).dengue can be prevented through protection against mosquito bites(repellent creams and sprays) and usage of nets, chemical larvacides temophos can be introduced to water bodies(Hossain, Hossain, 2016).The World Health Organization(2018) stated that dengue has rapidly increased in the past decade. A recent estimate indicates 390 million dengue infectious, per year are reported. Another study indicates 3.9 billion people in 128 countries are at risk of been infected by dengue virus 2(The World Health Organization, 2018).
HIV is the initial stage of the virus AIDS (U.S. National Library of Medicine, 2018).which effects the immune system destroying CD4 cells ( Colleen,2018).The causative agent for HIV is Human Immunodeficiency virus (HIV).An HIV patient shows flu like symptoms(sore throat, fever, body rashers and headaches) within 2 to 4 weeks.(Colleen, 2018).Also other symptoms like fatigue, swollen lymph nodes, ulcers in the mouth and genitals, muscle aches, joint pains, nauseas, vomiting, night sweats and hypogonadism or poor production of sex hormones in either sex(Colleen,2018).HIV is diagnosed by ELISA(enzyme-linked immunosorbent assay)test. If ELISA test is positive the western blot test is conducted to confirm(The Regents of the University of California, 2018). If diagnosing a before 18 month old the most sensitive test that could be conducted is the HIV DNA PCR test(Hossain, Hossain, 2015) if two negative HIV DNA PCRs within 3 months of life, it indicates the infant is not infected, although this is confirmed by the loss of transplacental maternal HIV antibodies from the infants circulation after 18months of age. (Hossain, Hossain, 2015).HIV could be prevented through blood screening, using clean needles, through protected sex(condoms) , infected pregnant women can get treated to reduce the risk of passing down the virus to the baby, infected mother’s should avoid breast feeding.36.9 million people around the world are living with HIV/AIDS in 2017.15 million are below the age of 15. Reportedly 1.8 million people were newly infected in 2017 which indicates 5000 newly infected individual per day .most HIV/AID cases are reported in African countries due to the lack of knowledge. However the amounts of deaths caused due to HIV/AID have been reduce more than 51% since the peak in 2004(Global Statistics, 2018).
Hepatitis is a condition commonly caused due to a viral infection but there are other possibilities as well such as autoimmune hepatitis caused as a secondary result of medication, drugs, toxins and alcohol (Kahn, Higuera, 2017).There are 5 types of hepatitis viruses. Hepatitis A,B,C,D and E. The causative agent for hepatitis is Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D (an defective virus) and Hepatitis E virus. Hepatitis has nonspecific symptoms in the initial stage where many recover at this stage and remain anicteric. However after 1 or 2 weeks patients develop jaundice, Deeping of jaundice, dark urine, pale stool, tender lymph nodes and in severe acute hepatitis, renal failure, arthritis and myocarditis can occur (Hossain, Hossain, 2016). Hepatitis A,B and C are diagnosed by physical examining and blood test, sometimes sonogram, CT scans and liver biopsy are also done, Hepatitis D and E are diagnosed through blood test. Hepatitis could be prevented through vaccinations, consuming uncontaminated food, blood screening, protected intercourse and using uncontaminated needles (Hossain, Hossain, 2016).The World Health Organization (2018) stated 55 to 85% people will develop HCV infection and 71 million people around the world are already living with the disease. Every year 350000 to 500000 die due to hepatitis complications (World Health Organization, 2018).
Most deaths caused around the world are due to Non infectious /non communicable diseases (Department of census and statistics, 2017, p.16). Each year nearly 38 billion people around the world die due to non infectious diseases. 70% of Sri Lanka’s diseases burden is due to non communicable diseases (Department of census and statistics, 2017). Infectious/communicable diseases spread is limited and the amount of death caused is less in the world due to expanded program of immunization (EPI) (Communicable disease Epidemiological profile, 2010). Immunization prevents illness like Rubella, Measles, Mumps, Influenza, Hepatitis B, Tetanus and ect (Common wealth of Australia, 2010). However the World Health Organization (2018) states if global immunization increases 1.5 million deaths occurred due to infectious diseases can be avoided.