Virology - HackMD

# Virology ###### tags: `共筆` ## Introdution ### Classification #### Baltimore classification 1. Group I：雙鏈DNA病毒(dsDNA viruses) 2. Group II：單鏈DNA病毒(ssDNA viruses) 3. Group III：雙鏈RNA病毒(dsRNA viruses) 4. Group IV：正股單鏈RNA病毒((+)ssRNA viruses) 5. Group V：負股單鏈RNA病毒((-)ssRNA viruses) 6. Group VI：單鏈RNA反轉錄病毒(ssRNA-RT viruses) 7. Group VII：雙鏈DNA逆轉錄病毒(dsDNA-RT viruses) <table style="text-align: center;background-color: white;width:100%"> <tr> <th colspan="3" style="text-align:center;">DNA病毒</th> </tr> <tr> <td>具套膜(Enveloped)</td> <td colspan="2">裸露的(Naked)</td> </tr> <tr> <td>雙股(dsDNA)</td> <td>雙股(dsDNA)</td> <td>單股(ssDNA)</td> </tr> <tr> <td><a href="#Herpesvirus" style="color:limegreen">疱疹病毒(Herpes)</a> <a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1hfMJIaU#Hepatitis-B-virus" style="color:limegreen">肝炎病毒(HepaDNA)</a> <a href="#Poxvirus" style="color:indigo">痘病毒(Pox)</a></td> <td><a href="#Polyomavirus" style="color:limegreen">多瘤病毒(Polyoma)</a> <a href="#Papillomavirus" style="color:limegreen">乳突病毒(Papilloma)</a> <a href="#Adenovirus" style="color:limegreen">腺病毒(Adeno)</a></td> <td><a href="#Parvovirus" style="color:limegreen">細小病毒(Parvo)</a></td> </tr> </table> <table style="text-align: center;background-color: white;width:100%"> <tr> <th colspan ="4" style="text-align:center;">RNA病毒</th> </tr> <tr> <td colspan="3">單股</td> <td rowspan="2" style="vertical-align:text-top;">雙股</td> </tr> <tr> <td colspan="2">正股(+)</td> <td >負股(-)</td> </tr> <tr> <td>裸露</td> <td>具套膜</td> <td>具套膜</td> <td>裸露</td> </tr> <tr> <td><a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Picornavirus" style="color:limegreen">小RNA病毒(picoRNA)</a> <a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Calicivirus" style="color:limegreen">杯狀病毒(Calici)</a></td> <td>披膜病毒(Toga) 黃質病毒(Flavi) <a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Coronavirus" style="color: orange">冠狀病毒(Corona)</a> <a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Retrovirus" style="color: orange">反轉錄病毒(Retro)</a></td> <td>布尼亞病毒(Bunya) <a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Orthomyxo" style="color:orange">正黏液病毒(Orthomyxo) <a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Paramyxovirus" style="color:orange">副黏液病毒(Paramyxo)</a> <a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Rhabdovirus" style="color:red">桿狀病毒(Rhabdo)</a> 沙狀病毒(Arena) 絲狀病毒(Filo)</td> <td><a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Reovirus" style="color:limegreen">呼腸孤病毒(Reo)</td> </tr> </table> * 核殼(Capsids) > 二十面體(Icosohedral) > 複雜型 > 螺旋狀對稱(Helical symmetry) > 子彈型 --- ### Virion structure * Naked Capsid * 在環境中**穩定(stable)** * 可對抗酸、乾燥、proteases、detergents * 可由糞口傳染(fecal-oral route transmission) * Envelope * 在環境中**不穩定(labile)** * 必須在潮濕環境 * 靠飛沫傳染 ### Viral pathogenesis * Natural infections * Acute infection * Persistent infection * Latent infection: an extreme version. * Abortive infection > Without producing more infectious viruses * Subclinical infection > Asymptomatic infection * Syncytia (cell-to-cell fusion) * Herpesvirus * Paramyxovirus * HIV > M-tropic (CCR5, non-syncytia-inducing) > T-tropic (CXCR4, syncytia-inducing) * * 細胞癌化 * <a href="https://hackmd.io/@kdpnEvjITFKjDfPL7yyWUQ/S1Eo1vNTL#Human-T-cell-lymphotropic-leukemia-virus-HTLV-1">HTLV(Human T-lymphotropic virus)</a> > T-cell lymphoma * HBV(Hepatitis B virus) > Hepatoma(肝癌) * <a href="#Epstein-Barr-virus-EBV">EBV(Epstein-Barr virus)</a> > Nasal pharyngeal carcinoma(NPC;鼻咽癌) > Burkitt’s lymphoma * <a href="##HHV-8-Kaposi’s-sarcoma-associated-herpesvirus-KSHV">KSHV(Kaposi's sarcoma-associated herpesvirus)</a> > Kaposi sarcoma(肉瘤) * HPV(Human Papillomavirus) > <a href="#Oncogenic-human-papillomaviruses">Cervical(子宮頸)/oral cancers</a> * MCV(Molluscum contagiosum virus) > <a href="#Pathogenesis">Merkel cell carcinoma(侵略性皮膚癌)</a> --- ## Polyomavirus ### Properties * Naked icosahedral capsid * ds DNA circular genome associated with **histones** (form host cell) * Capsid: VP1, VP2, and VP3 * Non-structural proteins * ==Large T== > mRNA轉錄調控 > DNA複製 > 促進細胞生長(細胞複製有利於病毒DNA複製) > ->藉由inactivating p53 & Rb > Transformation * Small t > Viral DNA replication * **Small** genome -> few proteins ### Life Cycle #### Transcription & Replication * **Two** transcription units (in **opposite** directions) * ++Early++ proteins (**small and large T**) * ==Large T==: 1. 幫助DNA replication 2. enhance Late gene promoter 3. inhibit Early gene promoter > ->**Replication origin binding** activity + **Transcription factor** activity * ++Late++ proteins (**VP1,VP2, VP3**) * Differential splicing * Replication fork * ==Large T== > **Helicase** #### Assembly & Release * VP1, 2, 3: Cytoplasm->Nucleus > 因為細胞質有太多DNase * Permissive cells > 導致細胞死亡 * **Nonpermissive cells** > 只允許early gene表現 > 導致transformation of the cells ![](https://i.imgur.com/o6BR9Kf.png =400x) <h3 id="MCV">Pathogenesis</h3> |Virus|Disease| |---|---| |BK virus|Renal desease Hemorrhagic cystitis (出血性膀胱炎)| |JC virus|Progressive multifocal leukoencephalopathy (PML)| |Merkel cell virus|Merkel cell carcinoma| * Progressive multifocal leukoencephalopathy (PML, 進行性多灶性白質腦病) * **Rare**, progressive, **fatal**, demyelinating disease * Kills oligodendrocytes(寡樹突膠細胞) * JC virus很常見，病患多半有**免疫不全問題** ### Epidemiology * Polyomavirus infections are ubiquitous. * **Respiratory** transmission * Latent infection可能在**免疫抑制**(Immunosuppressed)的人中被重新激活 > ex: AIDS, 器官移植, 孕婦 --- ## Papillomavirus ### Properties * Naked icosahedral capsid * **circular** dsDNA (8kb wrapping histones) * 難培養，只生長於**分化中細胞**(differentiating cells) ### Life cycle #### Transcription & Replication * All mRNAs are transcribed in **one direction**. * URR (upstream regulatory region) * 6-8 early genes and 2 late genes * DNA replicates **bi-directionally** (Replication fork) * ++Replication and viral gene expression++ are controlled by **host transcription factors**. > 由皮膚或黏膜上皮細胞的differentiation state決定 * In non-differentiated basal cells > Uncoat, DNA入核 > E6 & E7: Increase in **cell division** * In the differentiated cells > E1 & E2: Bind to the replication origin, direct initiation of **DNA replication** * In terminal differentiation cells > L1 & L2: Viral **capsid proteins** * Papillomaviruse**從Basal lamina感染** > ->角質層可以抵擋HPV感染 ![](https://i.imgur.com/UKTMNXG.png =450x) ### Disease mechanism * **接觸傳染**(direct or sexual) * Papillomavirus type決定組織向性(Tissue tropism)與疾病表現(disease presentation) * 病毒造成**基底層(basal layer)的過度生長**，變成疣(warts) * 病毒造成的**不典型增生(dysplasia)** 可能造成癌化 * ==Koilocytosis(細胞挖空現象)==: Cytologic changes (vacuolated cytoplasm) indicating **HPV infection**. <h4 id="Oncopapilloma">Oncogenic human papillomaviruses</h4> |Disease|HPV type| |---|---| |Cervical cancer(子宮頸癌)|HPV 16 and 18| |Condyloma acuminata(尖形濕疣)|HPV 6 and 11| ->Only **minority** infections lead to cancer or warts * Oncogenic viral proteins * E5: Activates **EGFR** -> Promote growth * E6: binds **p53** and promotes its degradation * E7: binds to **p105RB** ### Epidemiology * Gardasil & Cervarix: Preventative vaccines <h2 id="Adeno">Adenovirus</h2> ### Properties * Naked, icosahedral with **fibers** (進入細胞的attachment protein) * Linear, ds DNA genome associated with **viral-encoded proteins** (not histones) ### Life cycle #### Transcription * Genes are transcribed from **both DNA strands** * Early mRNAs: transcribed from 5 early promoters Late mRNAs: transcribed from a **single late promoter** > Early promoter多可以有更好的調控 > Late promoter只有一個可以確保所有結構蛋白都被製造 * Differential splicing & **Polyadenylation** > Primary transcript->Cut at poly(A) site->Polyadenylate->Intron removal->Mature mRNA * Major Adenovirus proteins * E1A: **Activate transcription**, binds **p105RB** * E1B: Binds **p53**, blocks apoptosis * E2: Activate promoter, terminal protein in DNA (=> **Primer**) * E3, E4 & VA RNAs: ++suppress host immune and inflammatory responses++ * Capsid * DNA-binding protein #### Replication * **Strand displacement mechanism** * No Okazaki fragments * Primer: precursor of terminal protein (pTP, 80kD) * DBP: ssDNA binding proteins * DBP, pTP, and Pol are transcribed from E2 transcription unit ![](https://i.imgur.com/uHQDnZK.png =300x) ### Disease mechanism * 病毒感染黏膜上皮細胞(Mucoepitheli cells)，直接造成細胞損傷 |Disease|補充| |---|---| |Upper respiratory tract infections|++serotypes 4 and 7++| |Conjunctivitis(結膜炎)|**swimming pool** conjunctivitis| |Acute viral gastroenteritis(腸胃炎)|Major cause| |Hemorrhagic cystitis(出血性膀胱炎)|| |Tumors|in animals , ++NOT in human++| ### Epidemiology * 直接接觸、**飛沫傳染**、**泳池** * Adenoviruses主要感染**小孩** * Serotypes 4 and 7 vaccine for military use --- <h2 id="Herpes">Herpesvirus</h2> ### Property * Envelope, icosahedral capsid * Linear dsDNA genome * Able to ++persist for the life of the host++ (**latency**). * Can be reactivated into lytic cycle (productive infection). * **Ubiquitous** (world-wild distribution). * Envelope glycoproteins > used for **attachment**, **fusion** & **escaping immune control** * Tegument > 介於核殼(Capsid)與套膜(Envelope)的空間 > 含有host & viral proteins ### Life cycle #### Lytic phase ##### Transcription * Contains **unique regions** ( U ) & **repetitive sequence** ( R ) * Can splicing, transcript both side * Use **cellular** transcriptional machinery. * Gene regulation (cascade) * alpha genes (immediate early): Regulatory proteins * beta genes (early): Regulatory proteins, **DNA replication** * gamma genes (late): Regulatory proteins, **Structural proteins** ##### Replication * **Two** replication origins 1. DNA circularized (terminal repeats) 2. Virus encoated origin binding protein, helicase, primase and ssDNA binding proteins > **θ replication** 3. Late phase: **Rolling circle replication** > Concatemeric strand is made. ##### Release * 於**nucleus**組裝 * gamma protein ++嵌入內質網++ -> 於高基氏體進行**glycosylation** * Virions egress from the ++nucleus, ER, and Golgi++ -> **exocytosis** or **lysis** #### Latent infection * Latent as a **mini-chromosome** * LAT轉錄 -> 處理成siRNA -> **抑制alpha-gene表現** > HSV-1, HSV-2 in **sensory neurons** > EBV, KSHV in **B cells** * Episome (附加體) => 獨立於host gene外 #### Reactivation (latency -> lytic cycle) * **Suppression of immunity** can lead to viral reactivation. * Reactivation may cause **disease recurrence**. ![](https://i.imgur.com/Wno7K8l.png =600x) --- ### Herpesviruses(各論) <h4 id="Subfamily"> Subfamily</h4> |Subfamily|Property|Virus| |---|---|---| |Alpha|**Short** growth cycle **Rapid** spread Latent in neuron cells|<a href="#Herpes-simplex-virus-HSV-1-amp-HSV-2">HSV-1, HSV2</a> <a href="#Varicella-Zoster-virus-VZV">Varicella-zoster virus</a>| |Beta|Long growth slow spread|<a href="#Cytomegalovirus-CMV">Cytomegalovirus</a> <a href="#HHV-6-amp-HHV-7">HHV-6, HHV-7</a>| |Gamma|Grow primarily in epithelial cells and B cells Latent in B cells|<a href="#Epstein-Barr-virus-EBV">Epstein-Barr virus</a> <a href="#HHV-8-Kaposi’s-sarcoma-associated-herpesvirus-KSHV">Kaposi sarcoma-related virus</a>| --- <h4 id="HSV">Herpes simplex virus (HSV-1 & HSV-2)</h4> ##### Host cell * Primary target cells: Mucoepithelial cells * Latent in neurons ##### Pathogenesis * Direct **cytopathologic** effect * Syncytia caused by membrane-membrane fusion * Produce vesicular lesion (小水泡病變) * Immunity * 抗體無法對抗胞內病毒 -> 病毒可藉由cell-to-cell (syncytia)或latent infection++逃過免疫系統的檢查++ * **免疫反應**為造成臨床症狀的主因 ##### Disease * **Cold sores** (唇疱疹) > 感染疱疹病毒嘴破，**不可用類固醇**口內膏 * **Genital herpes** (生殖器疱疹) * **Gingivostomatitis** (齦口炎) > 單純泡疹病毒：口腔前半部 > 腸病毒咽峽炎：口腔後半部 * Herpetic whitlow (疱疹性指頭炎) * Herpes encephalitis (腦炎) (rare) ##### Epidemiology * Transmission: **Oral (saliva), sex, contact** * Lifelong infection, worldwide, no seasonal incidence * **Immunocompromised people** are at risk. <a href="#Subfamily">Back to Herpesvirus subfamily</a> --- <h4 id="VZV">Varicella-Zoster virus (VZV)</h4> ##### Disease * Primary infection: **Chickenpox (Varicella,⽔痘)** > Smallpox: 天花 * ++Latency++ (**neurons**) infection: **Shingles (Zoster,帶狀疱疹)** > 會造成Postherpetic neuralgia(皰疹後神經痛) * Respiratory tract -> Viremia(病毒血症) -> Epithelial cell & Fibroblasts -> Neuron (Latency) 1. 感染後4~6天，受感染的**T細胞進入血液**，造成第一第一輪感染(**Primary viremia**) > 在成年人身上可能會引起由**強烈發炎反應**導致的肺炎(life-threatening **peumonia**) 3. 病毒入侵**肝臟、脾臟**與其他器官，釋放出來後造成第二輪感染(**Secondary viremia**) 4. 病毒入侵**皮膚**，在受感染後第二周左右造成第三輪感染(Vesicular rash of chicken pox) 5. 病毒感染感覺性神經節(**Sensory ganglia**)並潛伏於此(Latent infection) * 在**免疫不全病人**(Immunocompromised people)中可能會引起disseminated life-threatening disease * 帶狀疱疹會復發(**Recurrent disease**) * 併發症：於水泡中的**細菌感染**(Secondary bacterial infection)、病毒性**肺炎**(Viral pneumonia)、**腦炎**(Encephalitis)、**出血性水痘**(Hemorrhagic chickenpox) * VZV可穿越胎盤(Placenta)，造成**先天性水痘症候群（Congenital Varicella Syndrome）** > 發生率低(約3%) > 低體重、瘢痕性的皮膚病變、眼睛缺陷、四肢發育不全、中樞神經異常 ##### Epidemiology * Vaccine: Oka strain * Antiviral drugs: Acyclovir(靜脈注射), Valacyclovir(口服) <a href="#Subfamily">Back to Herpesvirus subfamily</a> --- <h4 id="EBV">Epstein-Barr virus (EBV)</h4> ##### Property * **Narrow** tissue tropism: **epithelial cells** of ++oropharynx++(口咽) and ++nasopharynx++(鼻咽), **B-lymphocytes** and some T-lymphocytes * **Ultimate B lymphocyte parasite** * EBV的**Latent gene**提供B細胞生長因子，維持B細胞的生長(**Immortalize B cells**) ##### Disease * **Infectious Mononucleosis**(單核球增多症) > Atypical T-cell (**Downey cell**): more ++basophilic++ and ++vacuolated++ cytoplasm * Burkitt’s Lymphoma(勃氏淋巴瘤) > c-myc translocation > 發生於**赤道非洲** * Post-Transplantation Lymphoproliferation disease (移植後淋巴球增生疾病；**PTLD**) * **Nasopharyngeal Carcinoma** (鼻咽癌) * Oral Hairy Leukoplakia (口腔絨毛狀白斑病) > **HIV**感染最常見的口腔病灶 ##### Epidemiology * 由**唾液(Saliva)**、直接口腔接觸傳染 -> Kissing disease * 在免疫不全病人(**Immunocompromised people**)上容易造成致命的腫瘤疾病(**fetal neoplastic disease**)(ex:PTLD) <a href="#Subfamily">Back to Herpesvirus subfamily</a> --- <h4 id="CMV">Cytomegalovirus (CMV)</h4> * Causes **latent infection** in ++myeloid stem cells, monocytes, lymphocytes, the stromal cells of the bone marrow++. ##### Disease * Asymptomatic carrier * Mononucleosis > CMV: Heterophile Ab **negative** > EBV: Heterophile Ab **positive** * Cytomegalic inclusion disease (CID) (經由**胎盤**傳染) * Small size * Thrombocytopenia (血小板減少) * Microcephaly (小頭畸形) * Jaundice * Hepatosplenomegaly (肝脾腫大) * rash > **Cytopathic effect(CPE)**: > Giant cells with " owl's eye" basophilic intranuclear and perinuclear **cytoplasmic inclusions** ##### Epidemiology * Infection by **oral/respiratory route**. * Transmission: **blood, organ transplants & all secresions** * Opportunistic disorder > Babies, blood and organ recipient & Immunocompromised people are at risk * 新生兒可藉由**母乳**感染CMV <a href="#Subfamily">Back to Herpesvirus subfamily</a> --- <h4 id="HHV">HHV-6 & HHV-7</h4> * **Lymphotropic** & ubiquitous * Roseola infantum (玫瑰疹) ``` The five most common childhood viral exanthems (rashes) • Measles 麻疹 • Rubella 德國麻疹 • Varicella (or chickenpox) 水痘 • Fifth disease (Slapped cheek syndrome) 第五病 • Roseola 玫瑰疹 ``` <a href="#Subfamily">Back to Herpesvirus subfamily</a> --- <h4 id="KSHV"> HHV-8 (Kaposi’s sarcoma-associated herpesvirus, KSHV) </h4> * AIDS- Kaposi’s sarcomas lesion * **Kaposi’s sarcoma** (卡波西氏肉瘤, KS, endothelial cell origin) * Primary effusion lymphoma (PEL, B-cell ymphoma) * Multicentric Castleman’s disease (MCD, B-cell lymphoproliferative disorder). <a href="#Subfamily">Back to Herpesvirus subfamily</a> --- <h2 id="Pox">Poxvirus</h2> ### Property * Pox -- skin lesions * The **largest** (>191Kb) and the most complex viruses * Linear, dsDNA genome with **fused ends** > Covalently closed hairpin ends: no free 3’ and 5’ ends * Double layer membrane * Dumbbell core * **Zoonosis** * **Cytoplasmic virus** > Own mRNA and DNA synthetic machinery ### Life cycle #### Transcription * Transcription, mRNA process 由病毒內含的酵素做用 * 每個基因都有自己的promoter * No spliced mRNAs (**no introns**) * Genes are distributed on **both DNA strands** * VETF (Packaged in virion) -> VITF (early proteins) -> VLTF (intermediate protein) * Early protein (uncoatase) -> DNA synthesis (factories) -> Intermediate and late proteins #### Early transcription * 病毒內含有： **RNA polymerase**, initiation proteins(VETF), RNA-processing enzymes 1. Initiated by virion-associated transcription factors (VETF), 產生VITF > 類似herpesvirus的tegument protein 2. VITF產生uncoatase => **Further uncoating of the DNA** > Poxviruses為特例：在完全uncoating前製造uncoating protein * Early proteins: DNA replication, RNA transcription, RNA modification and uncoating #### Late transcription * Occurs after **complete uncoating** and after **genome replication**. #### DNA replication * **Strand displacement** ![](https://i.imgur.com/fdQICGI.png =400x) #### Assembly * The virus gets “wrapped” by cellular membranes * Two **infectious** forms: * Intracellular mature virus (IMV): one lipid membrane > Released by host cell disintegration(解體) * Extracellular enveloped virus (EEV): two lipid membranes > Get out by budding through membranes ![](https://i.imgur.com/5D34OoC.png =500x) ### Disease * **Smallpox** (天花) * Initiated by **respiratory tract infection** * Spread mainly by the **lymphatic system** and cell-associated viremia (macrophages) * **Molluscum contagiosum** (傳染性軟疣) * ++Molluscum contagiosum virus (MCV)++ * 接觸性傳染 ### Vaccine * Immunization by **animal poxviruses**. * Given by a **bifurcated (two pronged) needle** * 天花根除原因 * Exclusive human host range * **Single serotype** * Consistent disease presentation with **visible** pustules(膿皰) * Vaccine: * Easy to administer * Presence of scar --- <h2 id="Parvo">Parvovirus</h2> ### Property * Parvo -- Small * Naked icosahedral capsid * **ss DNA** (+ or -) ### Life cycle #### Transcription * Two coding regions * Non-structural replication (rep) * Ori-binding protein * ATPase and helicase activities * Endonucleases * Transcription activators * Prevent infected cells from progressing through the cell cycle * Capsid (cap) * 1 ~ 3 transcriptional promoters * mRNA splicing #### Replication * Ends of the genome have **palindrome sequences** form hairpin loops (T-shaped) => **Primer** * **Strand displacement** * Synthase by **cellular DNA polymerase**, ++helped by viral protein++ * ITR: inverted terminal repetition => **Primer** ![](https://i.imgur.com/mNUexDr.png =450x) #### Replication cycle * Only ++one strand of DNA is packaged++(encapsidation) > 正股DNA(+ssDNA) or 負股DNA(-ssDNA)，平均隨機分布 ![](https://i.imgur.com/ZbyaWU6.png =500x) --- ### B19 virus * B19在有絲分裂旺盛的細胞(Mitotically active cells)中複製 * Perfer erythroid lineage cells(紅細胞株系): **Bone marrow** cells with ++P-Ag++ #### Disease * Erythema infectiousum (傳染性紅斑) (**fifth disease**) > A **mild rash** illness that occurs most commonly in **children**. * **Chronic hemolytic anemia** > 再生障礙性貧血危象(**Aplastic crisis**) * Spreads by **respiratory** and **oral** secretions. * Establishes large viremia and can cross the **placenta**. > Hydrops fetalis(胎兒水腫) > Anemia-related disease but not congenital anomalies(先天性異常) ### Adeno-associated viruses (AAVs) * **Dependovirus** * Replicate only when in association with a second **“helper” virus**, usually **adenovirus** (can be others, eg. Herpes). * Wild-spread, but do not cause illness