Types of Infectious Diseases

The Diseases caused by germs and which may infect any part of the body are called Infectious Diseases. They can spread by any means where there is a germ. They are caused by pathogenic microorganisms such as bacteria, virus, parasites and fungi. Germs can be spread by direct or indirect contact. Vaccination, maintenance of proper hygiene and medicines help in the prevention of infection.

·        Bacterial infectious diseases

·        Viral infectious diseases

·        Parasitic infectious diseases

·        Fungal infectious diseases

·        Mycobacterial diseases

·        Air borne diseases

·        Food borne diseases

·        Water borne diseases

·        Mosquito and tick borne diseases

·        Blood borne infectious diseases

·        Childhood infectious diseases or pediatric infectious diseases

·        Geriatric infectious diseases

·        Nosocomial infections or hospital acquired infections

·        Sexually transmitted diseases

·        Allergic infectious diseases

·        Neuro infectious diseases

·        Transplant infectious diseases

·        Topical infectious diseases

·        Tropical infectious diseases

·        Inflammatory infectious diseases

·        Opportunistic infections

·        Infectious diseases in pregnancy

·        Deadly infectious diseases

·        Rare infectious diseases

·        Communicable infectious diseases

·        Common infectious diseases

                                     Infectious Diseases in Plants

Plant Pathology is the study of diseases in plants caused by pathogens and environmental conditions. Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics and management of plant diseases.

 

·        Epidemiology

·        Biological control agents

·        Modeling of infectious diseases in plants

·        Phytopathology

·        Pathogen survival and dispersal of plant parasites

                                 Infectious Diseases in Animals

Animal Infectious Diseases is an important threat to human health, since the emergence of human diseases is dominated by zoonotic pathogens. Infectious Diseases affects livestock and also wild animals, focusing on characterizing the conditions for the pathogen spread and maintenance in the host population.

·        African swine fever

·        Rabies

·        Diseases causing microbes in animals

·        Parasitic diseases in animals

·        Clostridial diseases

·        Transmission of infections by animals

                                             Causes of Infectious Diseases

Infectious diseases can be caused by:

Bacteria. These one-cell organisms are responsible for illnesses, such as strep throat, urinary tract infections and tuberculosis.

Viruses. Even smaller than bacteria, viruses cause a multitude of diseases — ranging from the common cold to AIDS.

Fungi. Many skin diseases, such as ringworm and athlete's foot, are caused by fungi. Other types of fungi can infect your lungs or nervous system.

Parasites. Malaria is caused by a tiny parasite that is transmitted by a mosquito bite. Other parasites may be transmitted to humans from animal feces.

Direct contact

An easy way to catch most infectious diseases is by coming in contact with a person or animal who has the infection. Three ways infectious diseases can be spread through direct contact are:

Person to person. A common way for infectious diseases to spread is through the direct transfer of bacteria, viruses or other germs from one person to another. This can occur when an individual with the bacterium or virus touches, coughs on or kisses someone who isn't infected.

These germs can also spread through the exchange of body fluids from sexual contact or a blood transfusion. The person who passes the germ may have no symptoms of the disease, but may simply be a carrier.

Animal to person. Being bitten or scratched by an infected animal — even a pet — can make you sick and, in extreme circumstances, can be fatal. Handling animal waste can be hazardous, too. For example, you can acquire a toxoplasmosis infection by scooping your cat's litter box.

Mother to unborn child. A pregnant woman may pass germs that cause infectious diseases to her unborn baby. Some germs can pass through the placenta. Germs in the vagina can be transmitted to the baby during birth.

Indirect contact

Disease-causing organisms also can be passed by indirect contact. Many germs can linger on an inanimate object, such as a tabletop, doorknob or faucet handle.

When you touch a doorknob handled by someone ill with the flu or a cold, for example, you can pick up the germs he or she left behind. If you then touch your eyes, mouth or nose before washing your hands, you may become infected.

Insect bites

Some germs rely on insect carriers — such as mosquitoes, fleas, lice or ticks — to move from host to host. These carriers are known as vectors. Mosquitoes can carry the malaria parasite or West Nile virus, and deer ticks may carry the bacterium that causes Lyme disease.

Food contamination

Another way disease-causing germs can infect you is through contaminated food and water. This mechanism of transmission allows germs to be spread to many people through a single source. E. coli, for example, is a bacterium present in or on certain foods — such as undercooked hamburger or unpasteurized fruit juice.

                           Microbial Chemistry of Infectious Diseases

Microbial Pathogenesis is the study of the molecular mechanisms used by microorganisms to cause disease in humans and animals. By understanding how pathogens cause disease helps in the development of new therapeutic approaches. Virulence is the measure of the pathogenicity of an organism. The degree of virulence is related directly to the ability of the organism to cause infection despite host resistance mechanisms, it is affected by numerous variables such as the number of infecting bacteria, route of entry into the body, specific and nonspecific host defence mechanisms and virulence factors of the bacterium.

                                   Mechanism and Immunology of Diseases

Microbial Pathogenesis is the study of the molecular mechanisms used by microorganisms to cause disease in humans and animals. By understanding how pathogens cause disease helps in the development of new therapeutic approaches. Virulence is the measure of the pathogenicity of an organism. The degree of virulence is related directly to the ability of the organism to cause infection despite host resistance mechanisms, it is affected by numerous variables such as the number of infecting bacteria, route of entry into the body, specific and nonspecific host defence mechanisms and virulence factors of the bacterium.

                              Infectious Diseases & Food Microbiology

Microbiological hazards are one of the most significant causes of food poisoning. An understanding of these hazards is crucial to understanding how suitable controls may be applied  Food safety/quality  testing is required to obtain a certificate of analysis for ready to eat and raw products at certain stages of processing Food testing technologies such as Polymerase chain-reaction (PCR) testing identifies major pathogens like  E.coli0157:H7, Listeria monocytogenes, Salmonella and Campylobacter by detecting the organism's DNA  ELFA Enzyme-Linked Fluorescent Assay (ELFA) reveals pathogens by detecting their protein. Chemistry for Food Safety (FSMA) Such as Toxic Metals, Antibiotics, Mycotoxins, Melamine; Chemistry for Food Quality  such as pH, Total Solids, Water Activity, Nutrients Ingredients. Modern food safety has its roots in Chemical Aspects methods. Initially these methods were applied to extend the food testing  and over time an understanding emerged that many of these methods had the effect of making food safer for human consumption. Today these methods  are used widely in the global food sector as part of HACCP plans to consistently produce food for a mass consumption with high quality and safety

Clinical  Microbiology is the study of any microbes which can cause infection in humans. Because the focus is on human disease, this subject is often studied by the source of the specimen from the body – particular location, type of fluid or specific body tissue. Clinical microbiologists have to be able to tell the difference between normal microorganisms expected in a specimen and those causing an infectious disease. Classically, this is done by culturing the material on an artificial medium in the laboratory and solving the "mystery" of which bacteria, The two  major aspects of advances in microbiology are the discovery or isolation of new pathogens and the breakthrough in new technology. Of equal importance are some known pathogens which have taken on new roles either as the cause of a new clinical syndrome or as the leading cause of a known clinical syndrome. Adequate clinical management of infectious diseases relies primarily on the accurate identification of the causal micro-organism and the production of reliable information on its antimicrobial susceptibility. 

                             Infectious Diseases: Prevention and treatment

Infection Prevention and Control is helpful to prevent the transmission of infectious diseases. Aseptic technique is normally applied to prevent the infections caused by different means. Sterilization is another process of killing microorganisms by the application of heat. Disinfection is the process of killing harmful microorganisms. Some infectious diseases can be prevented by avoiding direct contact with the contagious person. Infections can also be controlled and prevented by creating public awareness on various infectious diseases and their outbreaks. Infections can be cured by various antibiotics and antimicrobials.

                        Detection and Preventing infections in Health care

Treatment of viral infections such as HIV involves patient care and moral support including antiretroviral therapy. Bacterial infections can be treated by administering antibiotics to the patients. Yeast infections can be primarily treated by sterilisation methods. Parasitic infections can be treated by antiparasitic drugs. Diseases such as Cancer can be treated by Chemotherapy. Recent techniques have proved that there is no disease that cannot be treated.

·        Anti cancers

·        Anti malarials

·        Disinfectants

·        Anti septics

·        Vaccines and vaccination

·        Chemotherapy

·        Traditional medicines

·        Herbal treatment

·        Interventional agents

·        Biopharmaceutical products

·        Biothreat agents

·        Anti biotics

·        Anti microbials

·        Anti bacterials

·        Anti virals

·        Anti retrovirals

·        Anti fungals

·        Anti parasitics

·        Anti mycobacterials

·        Anti inflammatory drugs and NSAIDS

·        Anti tubercular drugs

                               

The evolution of resistant strains is a natural phenomenon which occurs once microorganisms replicate themselves or when resistant traits are exchanged between them. The use and misuse of antimicrobial drugs enhances the emergence of drug-resistant strains. Designing safe and effective drugs specifically antiviral is difficult, because viruses use the host's cells to replicate. Recent reports showed that infection in human can occur by close contact with pets (dogs and cats). As cultural detection of some bacteria like Arcobacter is time consuming and not confirmatory, various DNA based protocols have been developed for rapid and accurate identification of Arcobacter species. phenotypic methods have been described for typing bacteria (including bio typing, serotyping and phage typing schemata), in the case of phage- and serotyping schemes, not widely available. Molecular epidemiology is the understanding of the pathogenesis of disease by identifying specific pathways, genes and molecules that influence the risk of developing disease. Reverse Zoonosis refers to Infectious diseases that are found in humans which can be transmitted to animals. Bacteria and viruses that are deadly to one type of creature can evolve quickly to infect another. Increasing human population, travel, and the global food business increase the likelihood that viruses will jump from animals into humans, the same factors ensure the reverse spread as well – often with dire consequences for zoological parks and wild and domestic animals. Hence the central element of modern technology treatment is the Nano patch™ array itself which consists of a 1 cm2 square of silicon with ~20,000 micro projections on its surface - invisible to the naked eye.

                                  Applied Diagnostic Microbiology

Diagnostic Microbiology and Infectious Disease also covers such areas as laboratory and clinical management of microbial diseases, epidemiology and pathogenesis of infections, automation in the diagnostic microbiology laboratory, and antibiotic susceptibility testing.

                                  Microbial Vaccines and Drugs

A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing micro-organism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and keep a record of it, so that the immune system can more easily recognize and destroy any of these micro-organisms that it later encounters. Vaccines can be prophylactic (example: to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or therapeutic (e.g., vaccines against cancer are also being investigated).

                              Improving Infectious Disease Surveillance               

Clinical Studies helps in inventing new treatment methods which helps in providing effective treatment. Case reports on infectious diseases includes research, biology, epidemiology, clinical aspects of all infection related diseases.

                                Improving Public Health Practise

Public health research and practice are credited with many notable achievements, including much of the 30-year gain in life expectancy in the United States over the 20th century. A large part of this increase can be attributed to provision of safe water and food, sewage treatment and disposal, tobacco use prevention and cessation, injury prevention, control of infectious diseases through immunization and other means, and other population-based interventions. Despite these successes, many additional opportunities to improve the public’s health remain. To achieve state and national objectives for better population health, more widespread adoption of evidence-based strategies has been recommended. Increased focus on evidence-based public health (EBPH) has numerous direct and indirect benefits, including access to more and higher quality information on what works, a higher likelihood of successful programs and policies being implemented, greater workforce productivity, and more efficient use of public and private resources.