Apurba S Sastry Microbiology Book PDF (3rd Edition) - Microbiology

Chapter 35  Malaria and Babesiosis 359 less severe anemia and no periodicity seen in fever cycle. The disease is more severe in splenectomized and immunocompromised patients ™™ Epidemiology: Babesiosis is endemic in temper...

Chapter 35  Malaria and Babesiosis 359 less severe anemia and no periodicity seen in fever cycle. The disease is more severe in splenectomized and immunocompromised patients ™™ Epidemiology: Babesiosis is endemic in temperate area of USA and Europe; not reported from India yet ™™ Diagnosis: Peripheral blood smear examination reveals ring forms inside RBC arranged in pair or tetrads (called as Maltese cross forms) (Fig. 35.8). It is often confused with the multiple ring forms of P. falciparum, but can be A B differentiated by lack of pigments and lack of crescentic Figs 35.8A and B: Giemsa stained blood smear showing Maltese gametocytes cross form: A. Schematic diagram; B. Peripheral blood smear. ™™ Treatment: Atovaquone plus azithromycin is given for Source: B. DPDx Image Library, Centers for Disease Control and Prevention treatment. (CDC), Atlanta (with permission). EXPECTED QUESTIONS I. Write essay on: a. Merozoite b. Sporozoite https://t.me/docinmayking 1. A 54-year-old male from Chhattisgarh presented c. Trophozoite d. Gametocyte with fever, chills and rigor for a duration of four 2. Which is the infective form of the malaria parasite days. The patient developed convulsions prior to mosquito? to admission. He was started on ceftriaxone by a a. Merozoite b. Sporozoite private medical practitioner, but did not improve. c. Trophozoite d. Gametocyte On physical examination, muscle tone and tendon 3. Which stage of the malaria parasite causes reflexes were reduced. Anemia and splenomegaly relapse? were present. The blood sample was collected for a. Sporozoite b. Trophozoite peripheral blood smear examination which showed c. Merozoite d. Hypnozoites accole form, multiple ring forms and crescent shaped 4. Which is true about Plasmodium falciparum? gametocytes inside RBCs. a. High level of parasitemia a. What is the etiological agent based on history? b. It invades erythrocytes of all ages b. Write briefly about the life cycle of the etiological c. Its erythrocytic schizogony takes place in the agent. capillaries of internal organs c. Describe the pathogenesis, clinical manifesta- d. All of the above tions and complications produced. 5. Crescent-shaped or banana-shaped gametocytes d. What are the various diagnostic modalities? are seen in infection with: e. How will you treat this condition? a. Plasmodium vivax 2. An 18-year-old female from Udupi, Karnataka, b. Plasmodium falciparum presented with high-grade fever which rises every c. Plasmodium ovale third day with associated chills and rigor. Her blood d. Plasmodium malariae sample was subjected to a rapid diagnostic test 6. Appearance of fever paroxysm every 72 hours which revealed bands near pLDH line and control (Quartan periodicity of malaria) is seen in line, but no band near the HRP-II antigen line. infection with: a. What is the probable etiological agent based on a. Plasmodium vivax history? b. Plasmodium falciparum b. Describe a note on epidemiology of this clinical c. Plasmodium malariae condition. d. Plasmodium ovale c. What are the various diagnostic modalities? 7. Babesiosis is transmitted by bite of: d. How will you treat this condition? a. Anopheles b. Sandfly II. Write short notes on: c. Mite d. Tick 1. Cerebral malaria. 8. Maltese cross form is seen in: 2. Plasmodium knowlesi. a. Babesiosis b. Plasmodium ovale III. Multiple Choice Questions (MCQs): c. Plasmodium vivax 1. Which is the infective form of the malaria parasite d. Plasmodium malariae to man? Answers 1. b 2. d 3. d 4. d 5. b 6. c 7. d 8. a 358 Section 4  Bloodstream and Cardiovascular System Infections ™™ Resistance to antifolates such as pyrimethamine is due Anti-larval Measures to point mutation in DHFR (dihydrofolate reductase) ™™ Larvicide: Use of mineral oil or Paris green has been gene extensively used to kill mosquito larvae and pupae ™™ Resistance to artemsinins has not be reported yet ™™ Source reduction (to reduce the mosquito breeding however it is observed in experimental animals. sites): Includes environmental sanitation, water man- Monotherapy with artemisinins is banned in India as it agement and improvement of the drainage system promotes resistance. ™™ Biological larvicide: Gambusia affinis (fish) and Bacillus thuringiensis (bacteria) can be used to kill the mosquito WHO Guideline for Assessing Degree of Resistance larva. Antimalarial drug resistance is detected by in vivo and in vitro methods. Vaccination for Malaria In vivo method (2002): The degree of resistance is assessed Despite of intense research, till date, there is no vaccine based on two factors—persistence of clinical manifestations licensed for human use. Currently, there are several and level of parasitemia following administration of the vaccine trials going on globally in Africa, Asia and America. antimalarial drug. Approaches are made targeting the various stages of In vitro tests: Various in vitro methods are also available malaria cycle. for antimalarial drug susceptibility testing such as: ™™ Pre-erythrocytic vaccine targeting sporozoites and ™™ The WHO in vitro micro test using RPMI 1640 medium liver schizonts: Aims at preventing infection, disease ™™ ELISA for measurement of HRP-II or pLDH and transmission https://t.me/docinmayking ™™ PCR to detect the P. falciparum specific drug resistance ™™ Erythrocytic vaccine targeting merozoites, blood genes. schizonts: These vaccines help in preventing the disease thus, are useful for people living in hyperendemic areas Prophylaxis against Malaria of malaria Prophylaxis against malaria includes chemoprophylaxis, ™™ Sexual stage vaccine targeting gametocytes: They are vector control strategies and vaccine prophylaxis. transmission-blocking; do not have prevent malaria in the individual taking the vaccine, but antibodies are passed Chemoprophylaxis to the mosquito during blood meal, block the further Chemoprophylaxis is recommended for travelers, migrant transmission of the parasite. laborers and military personnel exposed to malaria in The main problems in malaria vaccine include: highly endemic areas. ™™ The vaccine candidates are poor inducer of cell-mediated ™™ For short-term chemoprophylaxis (6 weeks): Mefloquine RTS, S/AS01 is recommended at a dose of 5 mg/kg weekly and It is the only vaccine candidate that has successfully administered two weeks before, during and four weeks completed phase III trial. It is pre-erythrocytic vaccine after leaving the area. containing Pf-CSP (circumsporozoite protein of P. falciparum) fused with hepatitis B surface antigen and a Vector Control Strategies chemical adjuvant (AS01). Vector control is still one of the prime weapon to control malaria in endemic areas. BABESIosis Anti-adult Measures Babesiosis is a malaria like illness seen in cattle and sheep. ™™ Residual spraying: Spraying the houses with residual B. microti is the most common species, others being B. insecticides such as dichlorodiphenyltrichloroethane bovis and B. divergens. It is similar to malaria parasite in (DDT), malathion and fenitrothion is highly effective its life cycle and pathogenesis except for the following against adult mosquito differences: ™™ Space application of pesticide in the form of fog or mist ™™ Hard tick (Ixodes scapularis) is the primary vector by ultra-low volume method of pesticide dispersion (definitive host) of the parasite ™™ Individual protection: Done by reduction of human ™™ There is no liver-stage, sporozoites enter directly into RBCs mosquito contact by using insecticide-treated bed nets, ™™ Clinical feature: It differs from falciparum malaria being repellents and protective clothing. less severe, low parasitemia, no cerebral involvement,  Chapter 35  Malaria and Babesiosis 357 Table 35.6: Treatment of Vivax Malaria (NVBDCP guideline, India). Table 35.8: Severe Malaria. Chloroquine 25 mg/kg, divided over three days, i.e. 10 mg/kg Characterized by ≥1 of the following features: on day 1 and 2 and 5 mg/kg on day 3 Impaired consciousness/coma Primaquine 0.25 mg/kg body weight; daily for 14 days; Repeated generalized convulsions should be given under supervision, aiming to kill Renal failure (Serum creatinine >3 mg/dL) hypnozoites of P. vivax (to prevent relapse) Jaundice (Serum bilirubin >3 mg/dL) Contraindicated in infants, pregnant women* Severe anemia (Hb 90% 5 parasites/µL in thick film good as a thick film