Filarial Parasites and Wolbachia
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Questions and Answers

What role does the endosymbiont Wolbachia play in relation to filarial parasites?

  • It causes periodicity in parasite appearance.
  • It is crucial for the survival of filarial parasites. (correct)
  • It enhances the immune response of the host.
  • It improves drug efficacy against the parasites.

Which of the following species is NOT mentioned as a filarial parasite?

  • Dirofilaria immitis (correct)
  • Brugia pahangi
  • Wuchereria bancrofti
  • Brugia malayi

Where do adult filarial worms primarily reside in the human body?

  • In the gastrointestinal tract
  • In the lymphatic system (correct)
  • In the bloodstream
  • In the respiratory system

Where is Brugia malayi notably prevalent?

<p>Indonesia and Malaysia (B)</p> Signup and view all the answers

What has been reviewed concerning filarial parasites?

<p>The physiological factors governing their periodicity. (A)</p> Signup and view all the answers

Which species of filarial worm is associated with significant prevalence in tropical Africa?

<p>Wuchereria bancrofti (D)</p> Signup and view all the answers

What characteristic is used to differentiate microfilariae species?

<p>Presence or absence of sheath (A)</p> Signup and view all the answers

What is noted about the periodicity of microfilariae?

<p>They can have different periodicity strains. (C)</p> Signup and view all the answers

Which of the following areas is NOT associated with the prevalence of W. bancrofti?

<p>Northern Europe (D)</p> Signup and view all the answers

How many common filarial species are mentioned?

<p>Five (A)</p> Signup and view all the answers

What factors characterize the different strains of filarial worms?

<p>Periodicity of microfilariae (D)</p> Signup and view all the answers

What is the significance of the caudal papillae?

<p>They aid in sensory perception. (B)</p> Signup and view all the answers

Which of the following statements about Brugia malayi is true?

<p>It is associated with lymphatic filariasis. (C)</p> Signup and view all the answers

What does genetic analysis of bancrofti populations in India indicate?

<p>Two strains are prevalent. (C)</p> Signup and view all the answers

What is the primary method of transmission for filarial worms like W. bancrofti?

<p>Vector-borne via mosquitoes (A)</p> Signup and view all the answers

How are the microfilariae described in their appearance?

<p>They are colorless and elongated. (A)</p> Signup and view all the answers

What stage of filarial parasites is primarily found in the blood of the host?

<p>Microfilariae (D)</p> Signup and view all the answers

Which of the following is a characteristic of noxurnally periodic W. bancrofti?

<p>Absence of appendages (A)</p> Signup and view all the answers

What factors can influence the periodicity of microfilariae in the bloodstream?

<p>Body temperature and vector feeding rhythm (C)</p> Signup and view all the answers

Which of the following statements is true regarding the geographic distribution of lymphatic filariasis?

<p>It can occur in Asia and Africa. (D)</p> Signup and view all the answers

How many genetically determined physiological races exist in W. bancrofti and B. malayi?

<p>Three (B)</p> Signup and view all the answers

Which animal models are mentioned as those that do not exhibit any orientation to host circadian rhythm?

<p>Litomosoides carinii (C), Dipetalonema viteae (D)</p> Signup and view all the answers

What best describes the form of the adult filarial parasites mentioned in the context?

<p>Cylindrical and non-segmented (A)</p> Signup and view all the answers

What is a common outcome of the fluctuation in the number of microfilariae in the bloodstream?

<p>Temporary disappearance (A)</p> Signup and view all the answers

What is the predominant behavior of the larval parasites in the human bloodstream?

<p>They exhibit a consistent nocturnal periodicity. (A)</p> Signup and view all the answers

What statistical measure indicates how well the nocturnal periodicity is fitted by a cosine function?

<p>r = 0.991 (B)</p> Signup and view all the answers

Which of the following regions exhibits the larval parasites in the human bloodstream?

<p>Polynesia and parts of Southeast Asia (A)</p> Signup and view all the answers

In the study, what does the geometrical approach refer to?

<p>The fitting of the biorhythm to a cosine curve. (D)</p> Signup and view all the answers

What parameter represents the amplitude of the population biorhythm in the cosine function?

<p>a (D)</p> Signup and view all the answers

How do the larval parasites typically synchronize their cycle?

<p>With their mosquito vectors (D)</p> Signup and view all the answers

What aspect of the larval parasites' behavior is examined in relation to time?

<p>Nocturnal periodicity (A)</p> Signup and view all the answers

What does the parameter 'k' represent in the equation for fitting the periodicity?

<p>Phase shift of the curve (D)</p> Signup and view all the answers

What geometric representation is used for a cosine function in the context of biorhythms?

<p>Polar coordinates (C)</p> Signup and view all the answers

What is the implication of the hypothesis regarding genetic determinism in human lymphatic filariasis?

<p>Biorhythms are ruled by two co-dominant alleles (C)</p> Signup and view all the answers

Which of the following biorhythm genotypes is NOT presented in the study?

<p>DdD (B)</p> Signup and view all the answers

What is the mean of several individual rhythms with the same period indicated as?

<p>Cosine function (A)</p> Signup and view all the answers

How many biorhythms on the same subject were analyzed over 15 months?

<p>10 biorhythms (A)</p> Signup and view all the answers

What are the possible combinations of alleles mentioned for the biorhythm genotypes?

<p>DD, Dd, dd (A)</p> Signup and view all the answers

What is the main focus of the hypothesis presented in the study?

<p>The relationship between biorhythms and genetic diversity (B)</p> Signup and view all the answers

What type of periodicity in biorhythms is being studied in relation to lymphatic filariasis?

<p>Circadian periodicity (A)</p> Signup and view all the answers

What does the dominant mutation in the circadian clocks of individual parasites indicate?

<p>The clocks of parasites are set at midnight. (B)</p> Signup and view all the answers

What is suggested about the age of the dominant mutation affecting parasite circadian clocks?

<p>It is shared by several biologically diverse parasites. (A)</p> Signup and view all the answers

Which type of periodicity is observed in W.bancrofti?

<p>Diurnal subperiodicity. (C)</p> Signup and view all the answers

Which of the following best describes the behavior of larval forms of the parasite?

<p>They exhibit complex circadian behaviors. (B)</p> Signup and view all the answers

What does the Hardy-Weinberg law imply about the genotypes of the parasites?

<p>They follow a predictable distribution of alleles. (B)</p> Signup and view all the answers

What is the significance of the peak hours for B.malayi being unknown?

<p>It may affect how they interact with their vectors. (D)</p> Signup and view all the answers

What aspect of filariasis do the described biting cycles relate to?

<p>Temporal relationships with vectors. (A)</p> Signup and view all the answers

Which statement best describes the behavioral types of the parasites?

<p>They show both diurnal and nocturnal activity patterns. (A)</p> Signup and view all the answers

What role does the sub-continent play in relation to the parasites mentioned?

<p>It is a key area for the identification of species. (A)</p> Signup and view all the answers

Which of the following best describes the significance of the circadian rhythm in relation to microfilariae?

<p>It is linked to the timing of microfilariae in the bloodstream. (A)</p> Signup and view all the answers

What impact does genetic analysis have on understanding W. bancrofti populations in specific regions?

<p>It uncovers genetic variations within populations. (D)</p> Signup and view all the answers

How is the periodicity of microfilariae typically described?

<p>It can be influenced by host activities and environmental cues. (C)</p> Signup and view all the answers

What does the dominance of a mutation in the circadian clocks of individual parasites indicate?

<p>It could influence the synchronization of their life cycle. (B)</p> Signup and view all the answers

Which of the following factors influences the periodicity of microfilariae in the bloodstream?

<p>Host's circadian rhythm (C)</p> Signup and view all the answers

What characteristic is used to differentiate between the species of microfilariae?

<p>Shape of the nuclei (B)</p> Signup and view all the answers

Which two species have genetically determined physiological races as part of their classification?

<p>B. malayi and W. bancrofti (D)</p> Signup and view all the answers

Where is B. timori localized?

<p>Lesser Sunda Islands (B)</p> Signup and view all the answers

What aspect of filarial parasite behavior is still not fully understood?

<p>Microfilarial periodicity (A)</p> Signup and view all the answers

What is the primary physiological difference among the three genetically determined races of W.bancrofti and B.malayi?

<p>Microfilarial periodicity (A)</p> Signup and view all the answers

Which characteristic is typical of nocturnally sub-periodic W.bancrofti?

<p>Release of microfilariae during night hours (C)</p> Signup and view all the answers

What factor is NOT likely to influence the periodicity of microfilariae in the bloodstream?

<p>Blood composition of the host (B)</p> Signup and view all the answers

Where in the host's body do microfilariae tend to accumulate during the day in certain species?

<p>Lungs (B)</p> Signup and view all the answers

Which of the following regions is associated with the highest prevalence of W.bancrofti?

<p>Southeast Asia (B)</p> Signup and view all the answers

What distinguishes the microfilariae of Brugia malayi from other types?

<p>Length of the tail (C)</p> Signup and view all the answers

What type of behavior is least likely to be observed in larval forms of the filarial parasites?

<p>Orientation to host circadian rhythms (B)</p> Signup and view all the answers

What ultimately results from the fluctuation in the number of microfilariae in the bloodstream?

<p>Potential host symptoms and disease manifestation (B)</p> Signup and view all the answers

What is the primary effect of the brainworm on the ant's behavior?

<p>It leads to the ant clamping at the tip of grass blades. (D)</p> Signup and view all the answers

Which nematode is responsible for the majority of lymphatic filariasis cases?

<p>Wuchereria bancrofti (C)</p> Signup and view all the answers

How long do adult filarial worms typically live in the human body?

<p>10 years (B)</p> Signup and view all the answers

Which statement best describes the periodicity of microfilariae in the bloodstream?

<p>Microfilariae have nocturnal periodicity. (D)</p> Signup and view all the answers

In which regions are Brugia malayi infections primarily found?

<p>Southeast Asia (A)</p> Signup and view all the answers

What is the consequence of lymphatic filariasis in its most severe form?

<p>Leads to elephantiasis (B)</p> Signup and view all the answers

How many people are estimated to be infected by filarial worms worldwide?

<p>40 million (D)</p> Signup and view all the answers

What is a common living location for the microfilariae in humans?

<p>Bloodstream (B)</p> Signup and view all the answers

What is the periodic characteristic of microfilariae associated with W. bancrofti?

<p>Nocturnally periodic (D)</p> Signup and view all the answers

Which factor influences the orientation of larval forms of filarial parasites to their host's circadian rhythm?

<p>Host's activity patterns (C)</p> Signup and view all the answers

What type of behavior do B. malayi and W. bancrofti exhibit during their nocturnal periodicity?

<p>Fluctuating population density (B)</p> Signup and view all the answers

How do the larval parasites typically synchronize their circadian cycles?

<p>By the light-dark cycle (B)</p> Signup and view all the answers

Which of the following parameters represents the amplitude of the population biorhythm in the cosine function?

<p>Amplitude coefficient (D)</p> Signup and view all the answers

What term best describes the common outcome of fluctuations in the number of microfilariae in the bloodstream?

<p>Episodic variation (D)</p> Signup and view all the answers

What does the presence of subperiodic forms of filarial parasites indicate?

<p>Inconsistent host cycles (C)</p> Signup and view all the answers

Which genetic aspect is suggested to play a role in the circadian clocks of the parasites?

<p>Dominant mutations (C)</p> Signup and view all the answers

What is the definitive host for the Plasmodium parasite responsible for malaria?

<p>Mosquitoes (C)</p> Signup and view all the answers

Which characteristic is true about the different species of Plasmodium that cause human malaria?

<p>A few species can transmit malaria to humans. (A)</p> Signup and view all the answers

What is the primary life cycle characteristic of the Plasmodium parasite?

<p>It is a heteroxenous parasite. (A)</p> Signup and view all the answers

In what regions is malaria most prevalent?

<p>Tropical regions including Africa and Southern Asia. (B)</p> Signup and view all the answers

Which of the following statements regarding the life cycle and reproduction of Plasmodium is correct?

<p>Asexual replication occurs after syngamy in mosquitoes. (B)</p> Signup and view all the answers

Which of the following best describes the symptom impact of malaria based on the number of cases reported?

<p>Malaria is a leading cause of death among children under five. (C)</p> Signup and view all the answers

What kind of biorhythm is associated with the behavior of certain mosquito vectors?

<p>Circadian and possibly other periodic behaviors. (C)</p> Signup and view all the answers

What has been suggested about the genetic mutation affecting the circadian clocks of certain parasites?

<p>It is dominant and ancient, shared among various lineages. (A)</p> Signup and view all the answers

Flashcards

Lymphatic filariasis

A disease caused by filarial worms in the lymphatic system.

Filarial worms

Parasitic worms that cause lymphatic filariasis.

Brugia timori

A type of filarial worm.

Microfilariae

The immature stage of filarial worms found in the blood.

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W. bancrofti

A prevalent filarial worm species, found in specific regions.

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B. malayi

Another filarial worm species distributed in other regions.

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Lymphatic vessels and nodes

Locations in the lymphatic system where adult filarial worms reside.

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Sheathed microfilariae

Immature filarial worms with protective outer layers found in blood.

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Wuchereria bancrofti

A species of filarial parasite that infects humans.

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Brugia malayi

A filarial parasite prevalent in certain regions.

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Filarial parasites

Parasites that infect humans, causing filariasis.

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Survival of filarial parasite

Factors affecting the continued existence of filarial parasites in the body.

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Genetic analysis of filarial parasites

Study of filarial parasite genetic variation to understand different strains.

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In Vitro filarial culture

Growing filarial parasites outside a living organism in a lab setting.

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Periodicity of filarial parasites

The cyclical patterns of filarial parasites' presence in the body.

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Prevalence of filarial parasite strains

The frequency at which specific strains of filarial parasites are found.

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Periodicity

Periodicity refers to the fluctuation in the number of microfilariae (immature filarial worms) in the blood of a host. This number changes throughout the day and night.

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Nocturnal Periodicity

Nocturnal periodicity occurs when the number of microfilariae is highest in the blood during the night.

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Sub-periodic W. bancrofti

A specific type of filarial worm (W. bancrofti) with a sub-periodic pattern. The microfilariae levels fluctuate but not as clearly defined as nocturnal periodicity.

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Microfilariae (mf)

Immature, developmental stages of filarial worms which are found in the blood or skin of the host. They are often responsible for the spread of disease.

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How do microfilariae disperse?

Microfilariae are released into the circulating blood at night. They need to be ingested by a mosquito in order to continue their life cycle.

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Vector

A vector is an organism that transmits a parasite or disease from one host to another. In the case of filarial worms, the vector is a mosquito.

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Geographic Distribution

Filarial worms are not found everywhere. Their distribution is linked to certain geographical regions.

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Cosine Function

A mathematical curve used to model the cyclical pattern of filarial parasites' activity, with peaks and troughs.

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Amplitude (a)

The height of the cosine wave, representing the maximum density of filarial parasites in the blood.

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Period (k)

The time it takes for the cosine wave to complete one full cycle, representing the duration of the filarial parasite's activity cycle.

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Filarial Parasite Activity

The presence and density of filarial parasites in the blood, often varying significantly throughout the day.

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Nocturnal Periodicity in Different Regions

Filarial parasites exhibit different nocturnal periodicity patterns depending on the region and the presence of certain mosquito vectors.

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Free of Nocturnal Vectors

Areas where filarial parasites can be found at all hours of the day, typically in regions without nocturnal mosquito vectors.

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Genetic Purity

The state of a population where individuals have very similar genetic makeup, potentially influencing the nocturnal periodicity of filarial parasites.

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What is the hypothesis about filarial parasite periodicity?

The hypothesis suggests that the diversity of biorhythms in lymphatic filariasis is determined by two co-dominant alleles: D (for 'day') and d, which combine into three genotypes: DD, Dd, and dd.

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What are the different genotypes in filarial parasite periodicity?

The three possible genotypes are DD, Dd, and dd, resulting from the combination of two co-dominant alleles, D and d.

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What role do the alleles D and d play in filarial periodicity?

The alleles D and d are co-dominant, meaning both alleles contribute to the phenotype. They influence the diversity of the filarial parasite's biorhythms, explaining the observed variations in periodicity.

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What does 'co-dominant' mean in the context of filarial periodicity?

Co-dominant alleles means that both alleles, D and d, contribute to the observed phenotype, in this case, the diversity of filarial parasite rhythms.

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What is the significance of the hypothesis for filarial periodicity?

The hypothesis proposes a genetic basis for the variation in filarial parasite periodicity, suggesting that the diversity of biorhythms is determined by the combination of these two co-dominant alleles.

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Sum of rhythms

When multiple rhythms with the same period occur simultaneously, their sum (or mean) is also a cosine function with the same period.

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Vector representation

A cosine function can be visualized as a vector in polar coordinates: a line with a specific length (amplitude) and direction (phase angle).

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Circadian Diversity

The variation in the timing of biological processes, such as the release of microfilariae, among different filarial worm species.

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Dominant Mutation

A single genetic change that significantly alters the circadian rhythm of a species, like the shift in microfilariae release timing.

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Midnight Clocks

The circadian rhythm of certain filarial worms is set to be most active at midnight, leading to a predictable pattern of microfilariae release.

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2 p.m. Clocks

Some filarial worm species have a different circadian rhythm, with their microfilariae release peaking at 2 p.m.

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Old Mutation

A genetic change that has been present for a long time within a species, indicating its importance for survival and adaptation.

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Vector-Parasite Temporal Relations

The relationship between the time of the day when the parasite is most active and the time of the day when the vector (mosquito) is most active.

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Sub-periodic

A type of filarial worm periodicity where the release of microfilariae fluctuates throughout the day but does not follow a clear night or day pattern.

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Hardy–Weinberg Law

A principle that describes the distribution of different genotypes within a population, assuming there are no disturbing factors.

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Periodicity in Filarial Worms

The fluctuation in the number of microfilariae (immature filarial worms) in a host's blood over time, often following a daily pattern.

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What determines periodicity?

The diversity of biorhythms in lymphatic filariasis is determined by two co-dominant alleles: D (for 'day') and d, which combine into three genotypes: DD, Dd, and dd.

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Sub-periodic Periodicity

A type of periodicity where the number of microfilariae in the blood fluctuates throughout the day but doesn't follow a clear nocturnal or diurnal pattern.

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What causes elephantiasis?

Elephantiasis is a severe form of lymphatic filariasis, caused by filarial worms like Wuchereria bancrofti, Brugia malayi, and Brugia timori, which infect the lymphatic system, leading to tissue swelling.

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Where do adult filarial worms live?

Adult filarial worms reside in the lymph nodes, while the microfilariae, their immature forms, circulate in the blood.

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What is the periodicity of filarial worms?

Filarial worms exhibit periodicity, meaning the microfilariae show a cyclical pattern in their presence in the blood, accumulating in the lungs during the day and moving to the peripheral circulation at night.

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What is the geographic distribution of Wuchereria bancrofti?

Wuchereria bancrofti, a prevalent filarial worm species, is mainly found in the equatorial belt, responsible for ~90% of lymphatic filariasis cases.

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What is the geographic distribution of Brugia malayi?

Brugia malayi, another filarial worm species, is found in regions like China, Korea, India, Sri Lanka, and the Philippines, contributing to ~10% of lymphatic filariasis cases.

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What behavior does Dicrocoelium dendriticum induce in ants?

Dicrocoelium dendriticum, a parasite, alters the behavior of ants by developing into a brainworm that causes tetania, forcing the ant to clamp onto the tip of grass blades during specific times of the day.

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How are humans infected with Dicrocoelium dendriticum?

Humans are infected with Dicrocoelium dendriticum by consuming infected ant larvae, usually through unwashed vegetables.

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What is the vector of lymphatic filariasis?

The vector for lymphatic filariasis is a mosquito, which transmits the microfilariae from an infected person to another.

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What is the significance of microfilariae periodicity?

The cyclical pattern of microfilariae in the blood, influenced by the host's circadian rhythm, is crucial for the parasite's survival and transmission. The peak release times align with the mosquito vector's feeding activities.

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What are the different types of microfilariae periodicity?

There are two main types: nocturnal, where microfilariae are most abundant at night, and sub-periodic, where the peak fluctuates but doesn't follow a clear night/day pattern.

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How does the host's genetic makeup influence filarial periodicity?

The host's genetic makeup can influence the periodicity of microfilariae. Two co-dominant alleles, D and d, may determine the timing of release, creating different genotypes (DD, Dd, dd).

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What is the 'sum of rhythms' concept?

When multiple rhythms with the same period occur simultaneously, their combined effect is a cosine function with the same period. This explains the consistency of the cyclical pattern even with individual variations.

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How does the 'midnight clock' relate to filarial periodicity?

The 'midnight clock' metaphor refers to the circadian rhythm of some filarial worms, where microfilariae are most active at midnight, aligning with the mosquito's nocturnal feeding habits.

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Co-dominant Alleles

Two alleles (versions of a gene) that both contribute to the organism's phenotype, in this case, influencing the diversity of filarial parasite rhythms.

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Genotypes (DD, Dd, dd)

Combinations of the D and d alleles that determine how the microfilariae are released, creating different rhythms.

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What is the difference between nocturnal and sub-periodic periodicity?

Nocturnal periodicity means microfilariae are highest at night, while sub-periodic shows less clear fluctuation, not strictly day or night.

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What causes the fluctuation in microfilariae numbers?

The number of microfilariae in the blood fluctuates due to their accumulation and release in the host's body. It is influenced by the host's circadian rhythm, which is a 24-hour body clock.

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What is periodicity?

Periodicity refers to the cyclical patterns of microfilariae numbers in the blood, which vary throughout the day and night.

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What is the role of a vector?

A vector is an organism, like a mosquito, that transmits a parasite or disease from one host to another.

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What is the significance of geographic distribution?

Filarial worms are not found everywhere. Their distribution is linked to specific geographic regions.

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What are the 3 physiological races of W.bancrofti and B.malayi?

The 3 races are based on the microfilarial periodicity: Nocturnally periodic, Sub-periodic, and Diurnally periodic.

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What is the difference between nocturnal and diurnal periodicity?

Nocturnal periodicity means microfilariae are highest at night, while diurnal means they are highest during the day.

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Malaria's cause

Malaria is caused by a parasitic protozoan called Plasmodium, with five species affecting humans.

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Plasmodium's hosts

Plasmodium thrives between two hosts: mosquitoes (its definitive host where it reproduces sexually) and humans (its intermediate host where it reproduces asexually).

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Malaria's prevalence

Malaria primarily affects tropical regions, mainly in Africa, South America and Southern Asia, affecting 247 million people in 2021.

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Malaria's fatal impact

Malaria sadly claims 619,000 lives annually, making it a significant health concern globally.

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Diversity of Filariasis Periodicity

The timing of microfilariae release varies among different filarial worm species, influenced by mutations and their interaction with their hosts.

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Filarial Worms' Rhythms

Two dominant alleles, 'D' and 'd', determine the periodicity of filarial worms. They can result in a midnight, 2 p.m. or a sub-periodic rhythm.

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Filarial Worm's Hosts

Filarial worms have a complex life cycle. They develop in mosquitoes, which then transmit the worms to humans via bites.

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Co-evolution in Vector-Parasite Relations

Filarial worms and mosquitoes have evolved together, where the parasite's periodicity aligns with the mosquito's feeding habits.

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Study Notes

Biological Clocks and Parasite Rhythmicty

  • Biological clocks are a crucial part of parasite biology, driving their survival and transmission.
  • Parasites exhibit diverse life cycles, ranging from simple to complex, with multiple hosts involved.
  • Parasites are ubiquitous, affecting numerous vertebrates and invertebrates.
  • Humans are susceptible to approximately 300 helminth worm species and over 70 protozoan species.
  • Parasitic diseases remain major causes of morbidity and mortality worldwide.
  • Soil-transmitted helminth (STH) infections are among the most common infections globally, affecting 1.5 billion people.
  • Prevalence rates for Ascaris, Trichuris, and Hookworm are approximately 15%, 8%, and 8%, respectively.
  • Parasitic diseases are prevalent in the US, despite often being underreported.
  • Parasite life cycles involve intricate interactions with multiple hosts, from simple single-host relationships to complex networks including intermediate hosts.
  • Some parasites have evolved strategies manipulating the behavior of their intermediate hosts, such as ants infected with Dicrocoelium dendriticum.
  • Dicrocoelium dendriticum, often called the "lancet fluke," is one parasite that successfully manipulates ant behavior.
  • Infected ants exhibit behavioral changes, such as clamping onto vegetation, to maximize transmission to definitive hosts.
  • Parasites can use different host behavioral patterns to optimize their survival.

Filarial Worms and Lymphatic Filariasis

  • Filarial worms are nematodes that infect the lymphatic system.
  • The combined species affect approximately 40 million people worldwide, causing permanent incapacitation.
  • In severe cases, filarial worms cause elephantiasis.
  • Adult worms live about 10 years.
  • Filarial worms have distinctive life cycles involving mosquitoes.
  • Infected mosquitoes transmit the infective larvae to another host.
  • Microfilaria (the larval stage) exhibits periodicity, residing primarily in the peripheral circulation at night.
  • 32 of the 38 least developed countries have high rates of infection.
  • W. bancrofti accounts for about 90% of cases, found predominantly in the equatorial belt.
  • B. malayi and B. timori affect other regions globally.

Plasmodium and Malaria

  • Plasmodium is the etiologic agent of malaria.
  • In 2021, there were 247 million malaria cases globally and 608,000 malaria deaths.
  • Malaria is prevalent in tropical regions, including Africa, South America, and Southern Asia.
  • Five species of Plasmodium cause human malaria.
  • Malaria is transmitted to humans via mosquito bites.
  • Symptoms range from mild (fever, chills, headache) to severe (fatigue, confusion, seizures).
  • Malaria is a life-threatening disease, spread by mosquitoes.
  • It's preventable and curable; it does not spread from person to person.
  • Malaria parasites exhibit circadian periodicity.
  • Rhythms in temperature, light, and humidity help control parasite development and transmission.
  • Host factors also influence parasite development cycles.
  • The periodicity of Plasmodium, particularly its synchrony with the host's circadian rhythm.
  • Food intake and immune responses play critical roles in coordinating parasite development with host cycles.
  • The parasite's development may also be tied to host-based rhythms in things like temperature, light cycles, and blood glucose.
  • Malaria parasites have intrinsic clocks that synchronize with the host's circadian cycle influencing parasite development and release times.
  • Parasite synchrony with the host reduces the risk of premature parasite release.
  • Food intake may regulate the synchrony that the parasite has with the host's circadian rhythm.

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Parasites: Biological Clocks and Rhythmicities PDF

Description

This quiz explores the complex interactions between the endosymbiont Wolbachia and filarial parasites. It covers topics such as the habitat of adult filarial worms, prevalence in specific regions, and identification of various species. Test your knowledge on the role of these parasites in human health.

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